# US Department of Energy debunks Arctic Silver 5?



## RichF (Jul 17, 2019)

Arctic Silver 5's claimed thermal conductivity, according to the company: *8.7* W/(m·K).
The US National Renewable Energy Laboratory's study finding: *0.94* W/(m·K).

Narumanchi, Sreekant; Mihalic, Mark; Kelly, Kenneth; Eesley, Gary (2008). "Thermal interface materials for power electronics applications" (PDF). _11th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, 2008: ITHERM 2008: 28 - 31 May 2008_. IEEE. Table 2. doi:10.1109/ITHERM.2008.4544297.

The Dow paste performed to its claimed specifications. Not only that, it's a much less expensive product with higher performance.






I would have thought the company would have released an Arctic Silver 6 to deal with this exposure but apparently not enough people in the enthusiast community know about it. Almost every time I read about paste someone mentions AS5 and it's still prevalent in stores. So, here is the apparent beef.


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## FordGT90Concept (Jul 17, 2019)

Digging into the spreadsheet, this is for automotive cooling where 150C is common...

There's a pretty big asterisk on Shin-Etsu:


> The key to the good performance of the Shinetsu grease seems to be a high content of very conductive particles and an unknown solvent that enhances performance. This solvent is considered to be a trade secret. The solvent evaporates over time (a few weeks or months), so the viscosity of the grease increases over time. As a consequence, the Shinetsu grease is not as easy to work with as the Thermalcote 251G and Wacker Silicone P12 greases. It is not clear how reliable the Shinetsu grease will be over time.



Also don't know if these are electrically conductive.  Shin-Etsu probably is seeing how it is aluminum.

TC-5022 was apparently qualified by AMD back in 2005:





						DOW CORNING’S GREASE QUALIFIED FOR AMD PROCESSORS - PCSTATS
					

PCSTATS.com publishes leading hardware reviews and computer guides in addition to daily tech news that speaks to the computer enthusiast. Get the 'Stats and Stay Informed!



					www.pcstats.com
				




Performance-PCs has it and so does ModDIY but there are no good reviews 








						Dow Corning Thermal Compound TC-5022 (3.5g)
					

Dow Corning Thermal Compound TC-5022 (3.5g)




					www.performance-pcs.com
				











						Dow Corning TC 5022 Thermally Conductive Compound 3.5g
					

Buy Dow Corning TC 5022 Thermally Conductive Compound 3.5g for $9.99 with Free Shipping Worldwide (In Stock)




					www.moddiy.com
				




I'm starting to wonder if the mystery goop on HSFs is Dow Corning TC-5022.

There's a concern of pressure though...CPUs have high pressure in order to ensure no air bubbles and tight contact with the HSF.  Automotive inverters (what they were testing) are no where near as tight.  AS5 could preform the best at high pressure...


I want to see a review of TC-5022 compared to others, that's for sure.


Edit: Found a review of a HSF that says it has TC-5022 pre applied:





						Thermaltake ITBU CL-P0303 Review - Phoronix
					






					www.phoronix.com
				




TC-5121 underperformed AS5.  TC-5022 should be theoretically better but that pressure consideration...





						Thermal Compound Roundup – February 2012 | Hardware Secrets
					






					www.hardwaresecrets.com
				








Another consideration: endurance:


			https://www.nrel.gov/docs/fy17osti/68014.pdf


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## Space Lynx (Jul 17, 2019)

lmao wow.


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## AsRock (Jul 17, 2019)

Only Dow Corning i use is for transistors (never tried it or any other DC products), AS5 is all so my go to paste when dealing with CPU\GPU's,  worked for me for years and see know reason to pick any other really.

I have noticed  with AS5 that the paste should be changed about every 18 months, starts drying and cracking, hot parts of the year don't help.


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## FordGT90Concept (Jul 17, 2019)

Separating this because important...

Here's a presentation by the same author of the one linked in the OP a year later:


			https://www.nrel.gov/docs/fy09osti/45793.pdf
		

 They're like "Btech HM2 thermoplastic with embedded carbon fibers has a factor of 3 to 4 lower resistance than the best commercial greases." "From viewpoint of both performance and reliability, there is an industry trend towards bonded interface"

In other words, the more research they did, the more they got away from CPU/HSF applications and focused on automotive applications stressing efficiency concluding a thermoplastic adhesive is best. Btech HM2 has a shelf life of six months and is not simple to apply: 100 psi bond compression (<3 sec) at 190 ⁰C (resin temperature)


And I think this is the most recent work (2016) by the same author (I think it's the final):


			https://www.nrel.gov/docs/fy16osti/66754.pdf
		

Edit: Ooo, important hint on page 17: sintered (packed) silver has better endurance than soldering.

AS5 may not have better immediate thermal properties but it may have better long term thermal properties.


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## lexluthermiester (Jul 17, 2019)

FordGT90Concept said:


> Digging into the spreadsheet, this is for automotive cooling where 150C is common...


Have to agree with this.

As have many, I have personally done benchmark testing repeatedly over the years that have proven clearly that AS5 does the job it's advertised to do and within the specifications declared. The methodology used by the testers has to be called into question when the results stand in direct contradiction of an entire industry of builders and reviewers who have sung it's praises after extensive testing.


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## FordGT90Concept (Jul 17, 2019)

Yeah...by the end, they tested 40 different thermal greases all at the same low pressure (because of glass beads to ensure thickness is consistent) and 75C.  AS5 is actually one of the better ones.  I think about thirty were tested that didn't even qualify for further testing.


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## Space Lynx (Jul 17, 2019)

I just use my graphene piece from IC, works wonders for me and I never have any mess.


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## lexluthermiester (Jul 17, 2019)

lynx29 said:


> I just use my graphene piece from IC, works wonders for me and I never have any mess.


Been wanting to try those out.


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## xtreemchaos (Jul 17, 2019)

I use GD900 its -4c better than MX4 and costs £5 for 30g, ive put it on every rig ive built in the past 2 years and it performs well its very near gelid ex.


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## erocker (Jul 17, 2019)

In regards to Arctic Silver, 2008 was 11 years ago. It's old and just sub-par to what is on the market today.


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## delshay (Jul 17, 2019)

I hope someone does a similar test on LM Compound to confirm they conductivity rate. I'm a fan of Phobya Liquid metal thermal compound due to the way it bonds to the surface.


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## RichF (Jul 17, 2019)

FordGT90Concept said:


> AS5 may not have better immediate thermal properties but it may have better long term thermal properties.





AsRock said:


> I have noticed  with AS5 that the paste should be changed about every 18 months, starts drying and cracking, hot parts of the year don't help.


Looks like there is mystery here.


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## remixedcat (Jul 17, 2019)

diaper ointment? LMAO....


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## delshay (Jul 17, 2019)

Here is my laptop running Artic Silver5. It's about 4 to five years old paste as I can't be bothered to open it up. The idle temperature is high & it does hit the max temperature & throttle.

Acer Ferrari 1200 Laptop which I am posting with. Those with a keen eye will spot something rare & very unusual (custom modification built into the hardware).


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## Vario (Jul 17, 2019)

I've used a lot of X23 and AS5 is a better paste for consumer application. Better temperatures and more malleable to get the proper coverage.  X23 requires preheating to get it soft enough to spread.  The temperatures were worse than AS5.  I think X23 is a superior paste when it comes pre-silk screened.

For those who have negative opinions of AS5 compared to other consumer pastes,  it is probable that all consumer pastes underperform their marketing hype but only AS5 was tested in this particular study.


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## micropage7 (Jul 17, 2019)

what dow corning? never heard before, and i dunno if that paste is good why it not well known?


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## Grog6 (Jul 17, 2019)

I think they did not do a good test.

I've tested this personally, and it's not as good as AS5 claimed to be, but it was never below 8W/mK.

I can't explain it, but I think they're wrong, and probably didn't get it applied correctly.

You take a black heatsink, stick another black heatsink to it with the compound you want to test, add a thermally bonded resistor, and measure the temperature of the two blocks in contact.
Setting the block to test on a block of ice gives you a good cooling load, and the relationship between them all gives you the thermal conductivity.

You can even measure what's going into the ice, lol.

Black anodized heatsinks make it easy to use a thermal camera; the emissivity of a black anodized surface is ~1.0, or very close.
Thermocouples work too.

Dimethylsiloxane is not a silicone you want to get on your hands; I use it in rocket engine mixes.


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## FordGT90Concept (Jul 17, 2019)

micropage7 said:


> what dow corning? never heard before, and i dunno if that paste is good why it not well known?


Dow Corning is the largest silicon produce in the world.  It's owned by DuPont now.








						Dow Corning - Wikipedia
					






					en.wikipedia.org


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## lexluthermiester (Jul 17, 2019)

remixedcat said:


> diaper ointment? LMAO....


I saw that too! Tell me that doesn't strike you as wacky funny?


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## FordGT90Concept (Jul 17, 2019)

The funny part is mayonnaise was only 2C warmer than AS5 (35C vs 33C)...


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## lexluthermiester (Jul 17, 2019)

FordGT90Concept said:


> The funny part is mayonnaise was only 2C warmer than AS5 (35C vs 33C)...


But how long was that testing done? Hardware Secrets didn't state that info. They seemingly didn't test it long enough for the mayo to dry out and/or become rancid, after all mayo is a perishable food. AS5 is designed to dry out and become more effective over time. Most of the other purpose made thermal compounds are as well, with some exceptions. That was an excellent article! As amusing as it was informative.


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## AsRock (Jul 17, 2019)

RichF said:


> Looks like there is mystery here.



Not really, i just think it starts showing it age after 18 months. I do have some MX4 around to and find it about the same.

As we do not use a air conditioner temps this time of year get around 33-36c ambient in the room with the computers.  Which when i notice the computer temps get a little higher than i like i will change out the paste which as resulted in improvements in temps.

The shit just dries up, and probably should be changed after 2 years anyways, in fact due to do it again soon now although video cards still good although i believe i have had it only 8 or so months since my replacement only hitting 82c on a full load even with the high ambient we have right now.

Another factor is if the computer gets moved about which mine does time to time.


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## lexluthermiester (Jul 17, 2019)

If you all thought the Diaper Ointment was funny, take a look at this one a few months earlier;





						Thermal Compound Roundup – December 2011 | Hardware Secrets
					






					www.hardwaresecrets.com
				



And here's the one when they tested the mayo;





						Thermal Compound Roundup – October 2011 | Hardware Secrets
					






					www.hardwaresecrets.com
				



Interestingly, toothpaste seemed a decent performer until the water evaporated. Then there was this set of tests;
https://www.hardwaresecrets.com/thermal-compound-roundup-june-2011/5/ 
They tested lipstick... and it worked!


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## John Naylor (Jul 17, 2019)

Testing needs to be done in the environment the product it will be used in.  Unless you have better luck than i did with the wayback machine, you'd be well served to look up benchmarkreviews 80-way thermal test.  They had always produced the most detailed reviews on TIMs I have ever found as well as the best "Application Methods" testing,

Thermally they had AS5 and Shin Etsu G-751 tied for thermal performance.    We always used Shin Etsu for CPU TIM for the following reasons:

1.  AS5 was 2.5 times the price.
2.  AS5 requires about 7 weeks of curing at 30 hours of use per week .  So what you might say ?  I want to do all my testing, OCing and documentation on a new build before it leaves the test bench.  If I gotta wait 7 weeks to do that, it's not a situation I want to be bothered with.  We will retest the CPU core temps about every 6 months and that first set of numbers recorded can be be used as a baseline ... as it won't be a abseline for 7 weeks.
3.  It is electrically capacitive.  Yeah, OK you are in experienced user and yu figure the chances are 1 in a 1,000 that you will mess up ... well 0 in a 1,00 id better odds and why pay 2.5 times as much to bring in that risk.

I have not found Shin Etsu to lose effectiveness over time... it's been on this box since 2013 and it's still holding within 0.2 C.  I do not recommend use on GPus tho ... One can very easily get a cooler assembled before Shin Etsu starts to lose its workability.  But on a GPU waterblock, you have the GPU, 8 or more memory chips, maybeVRMs (25 surfaces) and that doesn't even include the backplate side.  So to get all those surfaces covered, you need more time ... for this task I have found  Gelid Extreme very workable.  I would still recommend it on older cards but not necessary with newer generation nVidia cards at least where power efficiency has made great strides in recent years

The industry has since taken a turn away from using TIM w/ thermal pads, only the GPU is deemed to get hot enough to warrant this effort and it is a lot of work.   EK for example has stopped including this recommendation, again at least on latest generation nVidia cards.   Can't speak to AMD as no user has requested a AMD based build w/ more than a $200 GFX card ... and I wouldn't recommend water coling in this price range.

_"PLACING THERMAL PADS ON PCB.Place thermal pads on chips so that numbers on chips match size of thermal pads. EKWB made sure users have more than enough pads to cover all surfaces that need to be covered to make block fully functional). EKWB recommends using small drops of electrically non-conductive(for example: EK-TIM Ectotherm, Arctic Cooling MX-2 ™, MX-4 ™ or GELID GC-Extreme™) thermal grease on each phase regulator (that is being covered with thermal pad) in order to even further improve the thermal performance of the EK-FC 780 GTX Class"_


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## newtekie1 (Jul 17, 2019)

FordGT90Concept said:


> There's a concern of pressure though...CPUs have high pressure in order to ensure no air bubbles and tight contact with the HSF. Automotive inverters (what they were testing) are no where near as tight. AS5 could preform the best at high pressure...



I think you are on to something here.  AS5 is a pretty thick paste, it doesn't spread all that easily.  And mounting pressure, in my experience with AS5, is very important.  I even remember some heatsinks having huge bolts that pressed right down on top of the center of the CPU to just put insane amounts of mounting pressure between CPU and heatsink.  Now that we have thinner pastes that spread easier, and perform just as well or better, all that junk has gone away.


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## Athlonite (Jul 17, 2019)

John Naylor said:


> 2. AS5 requires about 7 weeks of curing at 30 hours of use per week



Well that's just BS all it takes is about 24hrs of hard run then turn off let it cool down for 30mins then do it again hard run then cool down and by hard run I'm talking anything that'll get your CPU over 45~55°C for an hour at a time gaming or PI runs whatever tickles your fancy or install F@H and just let it run for 24hrs it'll have the same effect



newtekie1 said:


> I think you are on to something here.  AS5 is a pretty thick paste, it doesn't spread all that easily.  And mounting pressure, in my experience with AS5, is very important.  I even remember some heatsinks having huge bolts that pressed right down on top of the center of the CPU to just put insane amounts of mounting pressure between CPU and heatsink.  Now that we have thinner pastes that spread easier, and perform just as well or better, all that junk has gone away.



Using the dot and pressure method with AS5 is the wrong way to do it a dot the size of a grain of rice and use your finger in a rubber glove to evenly spread it across the IHS for a nice thin layer is what your wanting. Doing this way I've never had an issue with temps getting to high and always had complete coverage of the IHS


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## Vario (Jul 17, 2019)

Athlonite said:


> Well that's just BS all it takes is about 24hrs of hard run then turn off let it cool down for 30mins then do it again hard run then cool down and by hard run I'm talking anything that'll get your CPU over 45~55°C for an hour at a time gaming or PI runs whatever tickles your fancy or install F@H and just let it run for 24hrs it'll have the same effect
> 
> 
> 
> Using the dot and pressure method with AS5 is the wrong way to do it a dot the size of a grain of rice and use your finger in a rubber glove to evenly spread it across the IHS for a nice thin layer is what your wanting. Doing this way I've never had an issue with temps getting to high and always had complete coverage of the IHS


Thats how I do it as well.  Spread it with my finger in a plastic baggy.


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## newtekie1 (Jul 17, 2019)

Athlonite said:


> Using the dot and pressure method with AS5 is the wrong way to do it a dot the size of a grain of rice and use your finger in a rubber glove to evenly spread it across the IHS for a nice thin layer is what your wanting. Doing this way I've never had an issue with temps getting to high and always had complete coverage of the IHS



Spreading it like that can introduce air bubbles. I've used the dot method and had complete coverage with AS5 without a problem.  Even Arctic Silver themselves don't recommend the spread method on any processor with an IHS.  They either recommend the line or dot method.

Not that it really matters, no one should be using AS5 these days anyway.  There are better pastes for the same price.


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## lexluthermiester (Jul 17, 2019)

Athlonite said:


> Well that's just BS all it takes is about 24hrs of hard run then turn off let it cool down for 30mins then do it again hard run then cool down and by hard run I'm talking anything that'll get your CPU over 45~55°C for an hour at a time gaming or PI runs whatever tickles your fancy or install F@H and just let it run for 24hrs it'll have the same effect


No, he's correct. AS5 take several weeks to fully cure and reach maximum effectiveness.


Athlonite said:


> Using the dot and pressure method with AS5 is the wrong way to do it a dot the size of a grain of rice and use your finger in a rubber glove to evenly spread it across the IHS for a nice thin layer is what your wanting. Doing this way I've never had an issue with temps getting to high and always had complete coverage of the IHS


Both methods work fine.


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## remixedcat (Jul 17, 2019)

lexluthermiester said:


> I saw that too! Tell me that doesn't strike you as wacky funny?


I lost it when I saw that


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## xorbe (Jul 17, 2019)

Yeah I like how mayo was solidly mid pack lol. What have I learned.  To choose a paste/grease that doesn't dry out.


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## Steevo (Jul 18, 2019)

remixedcat said:


> I lost it when I saw that




I remember the olden days if testing everything under the sun. Like mineral oil and AS5 kicked everything out, but it only lasted a couple weeks in the vertical position.


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## freeagent (Jul 18, 2019)

AS5 takes 200 hours to cure. You can help it along greatly with some thermal cycles, but you will still see some change at around 200 hours.. You also shouldn't use a baggie on your finger.. bubbles, uneven spread etc.. I just use about a grain of rice in the center or slightly larger, mount your cooler, give it a bit of a titty twister and clamp it down. Good to go. Some of you guys make it out to be this terrible stuff, but really, its all in your application. Its not as forgiving as other compounds. So if you are new, you may have to experiment with your application technique. I used it almost exclusively for about 10 years, and I don't have a problem with it. I just ran out and used the Chill Factor III that came with my Thermalright coolers, and then I ran out of that and I liked it enough to try their TF8. Gotta say probably the best I've used so far.


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## FordGT90Concept (Jul 18, 2019)

I don't think AS5 ever really cures.  It thickens with time but it should never "dry out."

I have a large tube of AS5 that I probably bought back in 2005.  It's really hard to get out of the syringe but it still works.


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## freeagent (Jul 18, 2019)

I didn't say anything about drying out.. I used the term "cure" because those are their words, and so is the 200 hour figure, comes from them.


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## FordGT90Concept (Jul 18, 2019)

Arctic Silver Incorporated - Arctic Silver 5
					






					www.arcticsilver.com
				





> Due to the unique shape and sizes of the particles in Arctic Silver 5's conductive matrix, *it will take a up to 200 hours and several thermal cycles to achieve maximum particle to particle thermal conduction and for the heatsink to CPU interface to reach maximum conductivity*. (This period will be longer in a system without a fan on the heatsink or with a low speed fan on the heatsink.) On systems measuring actual internal core temperatures via the CPU's internal diode, *the measured temperature will often drop 2C to 5C over this "break-in" period*. This break-in will occur during the normal use of the computer as long as the computer is turned off from time to time and the interface is allowed to cool to room temperature. Once the break-in is complete, the computer can be left on if desired.


Why the heating/cooling cycles are important is because it is using thermal expansion/contraction to sinter the silver particles.  Once they all found their home and sintering is complete, the thermal properties won't change for thousands of cycles...then it will slowly decline over thousands of more cycles.  I don't think NERL explained why that is... but only thermoplastics don't do that.


I think I was referring to AsRock on the previous page on the "dry out" comment.  I think it's not dried out...it's sintered.  Think packed sand...that's pretty much what it is like.  That's a good thing, not a bad thing, for something that is "99.9% silver."


Edit: Yup, this is more what I was replying to:


AsRock said:


> Not really, i just think it starts showing it age after 18 months. I do have some MX4 around to and find it about the same.
> 
> As we do not use a air conditioner temps this time of year get around 33-36c ambient in the room with the computers.  Which when i notice the computer temps get a little higher than i like i will change out the paste which as resulted in improvements in temps.
> 
> ...



I find it interesting how Arctic Silver themselves never mention sintering.  Maybe they never knew it was called that and stumbled upon it? 


But yeah, looping back to the NERL study, they never tested AS5 in a sintered state.  That's why the thermal properties of it were way under what the manufacturer claims.  AS5 wasn't intend to be tested/used like that.


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## freeagent (Jul 18, 2019)

Sorry man!


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## remixedcat (Jul 18, 2019)

Steevo said:


> I remember the olden days if testing everything under the sun. Like mineral oil and AS5 kicked everything out, but it only lasted a couple weeks in the vertical position.


Next will be liquid cooling with belle delphine's bathwater


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## lexluthermiester (Jul 18, 2019)

Steevo said:


> Like mineral oil


Actually, I still use mineral oil for liquid cooling. You buy the right kind it works as well as water without all the downsides, but I digress...



remixedcat said:


> Next will be liquid cooling with belle delphine's bathwater


Seriously? Did you really need to go there?


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## remixedcat (Jul 18, 2019)

lexluthermiester said:


> Actually, I still use mineral oil for liquid cooling. You buy the right kind it works as well as water without all the downsides, but I digress...
> 
> 
> Seriously? Did you really need to go there?


I was required to by the government. They would have killed me if I didn't


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## Athlonite (Jul 18, 2019)

*it will take a up to 200 hours* the two underlined words are correct if you only use your PC like an office computer (ie: email, web browsing, word or xl) where as I've found that helping it along with hard cycles of heating and then cooling cuts that 200 hours down considerably so pretty much after 24hrs I know that's going to be the temps I'm getting for 3 years or until such time I take the HSF off for cleaning

FX8320 @ 4.0GHz 1.38V + Thermolab Baram + 2 fans in push/pull + AS5 spread very thinly and thermally cycled hard (ie: 50+ C to OFF multiple times in 24hrs) = 52 Degrees C running F@H on all cores and with gaming it was cooler 45~48 degrees C


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## lexluthermiester (Jul 18, 2019)

Athlonite said:


> *it will take a up to 200 hours* the two underlined words are correct if you only use your PC like an office computer (ie: email, web browsing, word or xl) where as I've found that helping it along with hard cycles of heating and then cooling cuts that 200 hours down considerably so pretty much after 24hrs I know that's going to be the temps I'm getting for 3 years or until such time I take the HSF off for cleaning
> 
> FX8320 @ 4.0GHz 1.38V + Thermolab Baram + 2 fans in push/pull + AS5 spread very thinly and thermally cycled hard (ie: 50+ C to OFF multiple times in 24hrs) = 52 Degrees C running F@H on all cores and with gaming it was cooler 45~48 degrees C


Didn't mean to offend you, no worries. I never really worried about it. Put it on, installed the cooler, ran a quick cycle of Prime95 and if everything was cool[pun intended], I sent it out the door.


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## Athlonite (Jul 18, 2019)

@*lexluthermiester*

No offence taken it's good to have discussion


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## FordGT90Concept (Jul 18, 2019)

Athlonite said:


> *it will take a up to 200 hours* the two underlined words are correct if you only use your PC like an office computer (ie: email, web browsing, word or xl) where as I've found that helping it along with hard cycles of heating and then cooling cuts that 200 hours down considerably so pretty much after 24hrs I know that's going to be the temps I'm getting for 3 years or until such time I take the HSF off for cleaning
> 
> FX8320 @ 4.0GHz 1.38V + Thermolab Baram + 2 fans in push/pull + AS5 spread very thinly and thermally cycled hard (ie: 50+ C to OFF multiple times in 24hrs) = 52 Degrees C running F@H on all cores and with gaming it was cooler 45~48 degrees C


There's no point to any of this with AS5.  You put it on, the temperatures fall 2C to 5C during "break in" and that's really it.

AS5 is perfectly fine 10 years after install with regular use.  Sintering means it degrades very slowly (doesn't even start to until 300+ cycles).




Sintered silver is actually in the negatives until it starts heading into the positives as they all pack in.


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## biffzinker (Jul 18, 2019)




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## lexluthermiester (Jul 18, 2019)

biffzinker said:


>


Phil's channel is great. He should have got the 40mm version.


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## FordGT90Concept (Jul 18, 2019)

biffzinker said:


>


Those results don't surprise me.  That thermal pad product can't fill the surface pores where most of the surface contact area comes from.  It also can't fill the gap if the HSF and IHS aren't perfectly flat.


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## Aquinus (Jul 18, 2019)

FordGT90Concept said:


> I don't think AS5 ever really cures.


Back when I ran 6870s I did a test after swapping out the thermal compound and I found that temperatures dropped over the span of 5 heating/cooling cycles. Curing might be the wrong word for it, but something definitely happens that improves heat transfer. I can't say why this is the case, maybe the heat helps the compound spread out more or maybe there is a structural change to the compound after it has been heated and cooled several times, I don't know... but I definitely have seen with my own eyes that it takes time for AS5 to perform as it should.


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## lexluthermiester (Jul 19, 2019)

FordGT90Concept said:


> Those results don't surprise me.  That thermal pad product can't fill the surface pores where most of the surface contact area comes from.  It also can't fill the gap if the HSF and IHS aren't perfectly flat.


Did you actually watch that video? His results were very good. Greg, over at Science Studio uses them almost exclusively because they work so well. Linus at LTT raves about them too... Not sure sure what your point here was..


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## FordGT90Concept (Jul 19, 2019)

It was 3-6C hotter than the thermal paste and those numbers won't improve with time.  My guess is the AMD HSF isn't as flat as the AliExpress HSF; hence, 3C hotter.


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## Grog6 (Jul 19, 2019)

These "Curing cycles" don't happen if you apply it correctly.

The Cycle thing is the mobilization of the silver particles in response to heat.

If you do it right, in a thin layer, it will only improve 1 or 2 % over time.

You want a <2 mil thick layer, filling the AIR voids in the HS to CPU surface; if you're seeing 10% changes, you're doing it wrong.

I've done indium solder; it's barely better than AS5, and much harder to do.


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## Vario (Jul 19, 2019)

I've been using AS5 for many years.

I have never noticed a big difference in temperatures between immediately after mounting and months or years later.  I have read a lot of detractors comments about it being a downside to AS5 that it requires a curing period.  I haven't noticed that issue.  If it drops in temperature, it isn't really much.

Another comment people frequently mention is that it is conductive.  It isn't.

I have also heard mention that it is that it is capactive and therefore dangerous for electronics.  I haven't had any issue with electronics that have had AS5 applied to them.  Perhaps it could destroy a device if it was inappropriately used.

I run AS5 on my CPUs and graphics cards, its given me more consistent results than any other paste.  It lasts a long time for me too.  I have a videocard I repasted in 2012 that is still working great.

If you look at comparisons of the typical non liquid metal pastes, you will find they are all very close together, typically differing by 1 to 3 degrees Celcius.  For this reason, the temperature isn't the only criterion for me, I like a paste that is easy to apply, has consistent performance, and doesn't change over time.  I also like the tackiness of AS5,  the paste doesn't shift and dislodge or thin out.

To apply it, I put my finger in a stretched plastic baggy and then put a drop of it on the surface I wish to apply to.  Then I spread it until the surface has a thin but uniform grey coating.

Today, playing GTA V for a couple hours, my 1060 with Arctic Mono Plus and AS5 paste didn't go over 50*C .  My 8600K with PHTC14PE and AS5 paste didn't go over 60*C at 4.6 GHz / 4.3 uncore and ~1.18V.  The room ambient is 27C.

https://www.tomshardware.com/reviews/thermal-paste-comparison,5108-9.html  Note that the temperature range in the 'paste in a tube' products from the best observed to the worst observed is only about 4 degrees.


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## FordGT90Concept (Jul 19, 2019)

You probably have air bubbles then.  AS5 should improve over cycles as the silver sinters.  It won't if there's air between the thermal surfaces.  Pre-spreading it is the best way to make air pockets.  Just because the temp diode doesn't have an air bubble directly over it doesn't mean there isn't one (or many) elsewhere.  It's better to have too much and it squish over the edge of the heat spreader (it's non-conductive...won't damage anything) than not have enough or risk air bubbles.


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## biffzinker (Jul 19, 2019)

FordGT90Concept said:


> (it's non-conductive...won't damage anything)


Hold up, Arctic Silver 5 is conductive, but a little bit over the edge of the heatspreader isn't going t ok hurt anything.


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## FordGT90Concept (Jul 19, 2019)

Arctic Silver Incorporated - Arctic Silver 5
					






					www.arcticsilver.com
				





> *Not Electrically Conductive:*
> Arctic Silver 5 was formulated to conduct heat, not electricity.


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## biffzinker (Jul 19, 2019)

FordGT90Concept said:


> Arctic Silver Incorporated - Arctic Silver 5
> 
> 
> 
> ...


But it also says: (While much safer than electrically conductive silver and copper greases, Arctic Silver 5 should be kept away from electrical traces, pins, and leads. While it is not electrically conductive, the compound is very slightly capacitive and could potentially cause problems if it bridges two close-proximity electrical paths.)


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## lexluthermiester (Jul 19, 2019)

FordGT90Concept said:


> Arctic Silver Incorporated - Arctic Silver 5
> 
> 
> 
> ...





biffzinker said:


> But it also says: (While much safer than electrically conductive silver and copper greases, Arctic Silver 5 should be kept away from electrical traces, pins, and leads. While it is not electrically conductive, the compound is very slightly capacitive and could potentially cause problems if it bridges two close-proximity electrical paths.)


Actually, you're both right.

AS5 is capacitive under certain conditions, but it is not directly conductive.

Can't remember where I read the article, but there was a test conducted on an OC site in 2009 to see what AS5's properties are and it was shown to be an electrical insulator at room temperature but once heat was applied above a certain range it became capacitive at voltages above 6.7v. So as long as you don't get it on 12v trace lines you'd be fine. So some friends of mine and I decided to test this ourselves and discovered it was correct, though our test showed it didn't start having problems until it got to 8v. We believe it was because we didn't apply enough heat as it was limited to 90C. We did this on a Core2Quad that was OC'd and then on a hot plate. We concluded that AS5 is safe for all but the most careless bungling doofus. 

So we need to keep it out of the hands of that guy from the Verge's PC build video... The Verge in general should avoid AS5.


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## Basard (Jul 19, 2019)

I burned thru a tube of some Gelid in less than five applications... left me with a sour taste in my mouth, it basically costs 20x what AS5 costs.  For such negligible difference in temp, I immediately went back to AS5.


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## purecain (Aug 17, 2019)

those scores are interesting... I thought a few of the pastes were better than they actually are.


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## lexluthermiester (Aug 17, 2019)

purecain said:


> those scores are interesting... I thought a few of the pastes were better than they actually are.


Read through the thread before taking those results seriously. The testing methodology had a flaw of some sort.


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## eidairaman1 (Aug 17, 2019)

FordGT90Concept said:


> You probably have air bubbles then.  AS5 should improve over cycles as the silver sinters.  It won't if there's air between the thermal surfaces.  Pre-spreading it is the best way to make air pockets.  Just because the temp diode doesn't have an air bubble directly over it doesn't mean there isn't one (or many) elsewhere.  It's better to have too much and it squish over the edge of the heat spreader (it's non-conductive...won't damage anything) than not have enough or risk air bubbles.



Have never had a problem using the recommended spread method, i set the sink down and press and twist twice and thats it


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## lexluthermiester (Aug 17, 2019)

eidairaman1 said:


> Have never had a problem using the recommended spread method, i set the sink down and press and twist twice and thats it


That's a good method.


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## eidairaman1 (Aug 17, 2019)

lexluthermiester said:


> That's a good method.



But i spread the thermal compound on the ihs/die first.

I do that with all compounds


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## FordGT90Concept (Aug 17, 2019)

purecain said:


> those scores are interesting... I thought a few of the pastes were better than they actually are.


TL;DR: The test was for automotive thermal greases so they wanted good performance for cheap.  The test didn't take into consideration sintering of silver until much, much later (which is what Arctic Silver 5 does).  By the time they figured that out, they discovered permanently bonded solutions are the best...which isn't practical for home computers (requires heat and pressure on an industrial scale).


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## eidairaman1 (Aug 17, 2019)

FordGT90Concept said:


> TL;DR: The test was for automotive thermal greases so they wanted good performance for cheap.  The test didn't take into consideration sintering of silver until much, much later (which is what Arctic Silver 5 does).  By the time they figured that out, they discovered permanently bonded solutions are the best...which isn't practical for home computers (requires heat and pressure on an industrial scale).



Hence mixing AS5 and ASEpoxy 50/50 for semi permenant solution (requires normal mechanical force to break the bond)


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## FordGT90Concept (Aug 17, 2019)

I was referring to Btech HM-2 which is a graphite thermoplastic:





						HM-2 Highly Thermally Conductive Film | Btech Corp
					

HM-2 Highly Thermally Conductive Film btechcorp has invented and patented a process for aligning high density fibers through the thickness of a polymer matrix... up to 20 million fibers per square inch.



					btechcorp.com
				



It's not an adhesive.  After the heatsink has been bounded with HM-2, you're going to break the metal on either side before you break the thermoplastic bond.


Looking at Arctic Silver Epoxy, it has a much lower content of silver than Arctic Silver 5 does so I doubt it performs as well.


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## plonk420 (Aug 17, 2019)

Vario said:


> Thats how I do it as well.  Spread it with my finger in a plastic baggy.



whew, i thought i was the only one xD


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## lexluthermiester (Aug 17, 2019)

FordGT90Concept said:


> Looking at Arctic Silver Epoxy, it has a much lower content of silver than Arctic Silver 5 does *so I doubt it performs as well*.


It does, I've used it in a number of applications over the years.


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## RichF (Aug 21, 2019)

I think it's highly dubious that silver would be a useful component — because it tarnishes. I think it's there (in whatever minuscule amount) for marketing magic and to justify the price tag. Copper oxides are terrible thermal conductors when compared with pure copper and I have no reason to expect silver oxides will be any better.


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## Grog6 (Aug 21, 2019)

Considering that silver sulfide is very black, and AS5 is gray, I think you're incorrect. 

Silicone oil is an amazing coating.

You are correct that most oxides are terrible conductors; but the only one I've ever seen used is beryllium oxide, which is what the white compound is made of.

They also used to make hard insulators for TO-3 and TO-220 transistors out of it.


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## RichF (Aug 21, 2019)

Grog6 said:


> Considering that silver sulfide is very black, and AS5 is gray, I think you're incorrect.


Yes the .00000001% of silver would affect the coloration in a strong way.


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## Pheckphul (Jun 30, 2020)

Grog6 said:


> <SNIP>
> 
> I've tested this personally, and it's not as good as AS5 claimed to be, but it was never below 8W/mK.
> 
> ...




I didn't read both documents word-for-word, I just scanned through them. I didn't notice that they spent the 200 hours with cooling and heating cycles that AS5 supposedly needs to become optimally effective.

Just because it's DOE doesn't mean the guys know WTF they are doing. Worked at Lawrence Livermore National Laboratory for several years and came across plenty of lazy idiots.


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## freeagent (Jun 30, 2020)

I've got nothing bad to say about AS5. I used it for nearly a decade and it was great. I would still be using it now, but I ran out and wanted to try something new.. glad I did because I don't see myself buying it anymore. Its still a good tim, just not as good as it used to be in these modern times.


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