# 4C/4T vs 4C/8T vs 6C/6T



## newtekie1 (Mar 1, 2018)

So I've had this discussion with a couple people, and it has been said that the reason Intel hasn't released a 4C/8T processor with Coffee Lake is that it would make the 6C/6T i5 processors pointless, because the Hyperthreading on 4 cores would equal 2 extra real cores.  I've even see people here on the forums say this.  But I don't believe Hyperthreading is that efficient, so I decided to test if a 4C/8T processor would match a 6C/6T.  Mainly to settle an argument between me and a coworker, but I figured I'd share the results here.

*Test Bed Setup:*

Intel i7-8700K @ 4.8GHz on all Cores
Hyprethreading disabled in the BIOS for 6C/6T tests
2 Cores disabled in the BIOS and Hyperthreading enabled in the BIOS for 4C/8T tests
2 Cores disabled in BIOS and Hyperthreading disabled in BIOS for 4C/4T tests

Corsair H110i GTX AIO Liquid CPU Cooler
AsRock Z370 Taichi Motherboard
32GB(4x8GB) Corsair Vengeance DDR4 @ 3000MHz
480GB Crucial MX200 SSD
PNY GTX1060 XLR8
Corsair HX850v2 PSU






*The Tests I did:*

*Cinebench R15 ST:* Pretty self explanatory.  For this test I ran the "Single Core" test, which only uses a single thread to render the image.  Ran 3 times on each configuration and averaged the scores from the 3 runs.  The result is the average score.
*Cinebench R15 MT:* Pretty self explanatory.  For this test I ran the test normally, which uses multiple threads to render the image, matching the number of threads use to the number of threads available on the CPU.  Also, ran 3 times on each configuration and averaged the scores from the 3 runs.  The result is the average score.
*HWBOT X265 Benchmark:* Another pretty self explanatory test.  Again, ran 3 times, and averaged the FPS of the 3 runs.
*MP3: * For this test I took 456 random MP3s with different bitrates and use dBPoweramp to batch convert them all using LAME Variable Bitrate Q-2.  The result is the encoding speed based on CD-ROM speeds.  So an encode speed of 1x would be the speed of a 1x CD-ROM(150KB/s), 2x would be the speed of a 2x CD-ROM(300KB/s), etc.
*7zip Compress/Decompress: * I ran the benchmark in 7zip version 18.01.  I let it run until 10 passes had completed.  The results is the MIPS after the 10 runs.
*Intel Burn Test: *I did 3 runs of Intel Burn Test v2.54 using the standard settings. I averaged the results of the 3 runs.  The results are the average GFLOPS.

I should note that I didn't do any game tests because I don't believe the GTX1060 is a strong enough GPU to properly do game CPU tests, and I don't have a stronger GPU available right now.  Plus, except for a few rare titles, adding threads beyond 4 either by HT or real cores doesn't really boost performance anyway.  I also purposely picked tests that are definitely Multi-threaded.

Results:









*Conclusion:*

To me it is pretty clear that in multi-threaded work loads, the 6 real cores outperform the 4C/8T.  Hyperthreading just does not provide the performance boost needed to match a 50% increase in core count.  *Edit:* _However, after doing the 4C/4T tests, I have to actually admit that Hyperthreading added more performance than I was expecting in some of the tests.  I expected HT to add about 25% performance, which we do see in the X265 test, but I was surprised to see over 40% increased in performance._

I also realize that this is a slightly flawed test due to the cache on the i7-8700k.  The 6C/6T processors only have 9MB of L3(or 1.5MB per core) while my 8700K has 12MB and the 4C/4T processors currently have 8MB of L3, meaning the 4C/8T processor would also likely have 8MB(or 2MB per core).  The extra cache of the 8700K is going to boost the numbers for both 4C/8T and 6C/6T slightly, but it is probably boosting the 6C/6T just a little more.  However, I don't believe this actually makes a significant difference.  *Edit:* _This is another area where I have to kind of rethink things.  While I still think that the cache likely didn't make a large difference.  I actually think that it may be helping the Hyperthreading more than I originally thought, to the point where it may actually be a wash.  Hyperthreading needs a lot of cache.  At the end of the day, the more threads you have the more cache you need.  So having 12MB will likely be more beneficial to a processor with 8 Threads than one with 6.  That is just what I'm thinking, I could be wrong, but in the end I don't believe the difference cache size made any significant difference._

*Edit: *_This is hopefully the last edit unless I decide to run more tests and add more data.  I wanted to address the single threaded test.  I added that because in the past there has been talk about how Hyperthreading hurts single threaded performance, even recommendations to disabled it to boost performance, especially in games. So, really, I was just curious how it behaves on modern processors.  You can take away from it that, yes, it does slightly lower single threaded performance.  It can be said that less than 1.5% difference is probably within margin or error.  However, I will say that the scores were extremely consistent in this test.  As I pointed out, I ran Cinebench 3 times on each configuration.  For the 4C/4T test the score was 204-204-204.  All three times, it ran and gave the exact same score.  The 6C/6T test was the exact same story, 206-206-206, the same score all 3 runs.  The only test that wasn't perfectly consistent was the 4C/8T test, it gave scores of 200-202-201, still pretty darn consistent.  So I can say that I'm confident in saying that Hyperthreading does slightly reduce single threaded performance.  However, I would not recommend ever disabling it at this point.  The very minor performance impact is not going to be noticeable.  However, the loss in multi-threaded performance will definitely be noticed.  And it is just not worth the hassle to go into the BIOS regularly to disable and enable Hyperthreading._

_Finally, if there is one thing these test do show, it is that on a 4 Core processor, Hyperthreading provides a definite noticeable performance boost in multi-threaded workloads.  To me, it seems foolish that Intel didn't release the 8th Gen i3 lineup without Hyperthreading and left no real spot in the product lineup to add 4C/8T processors.  Even if it was only the i3-8350K that had Hyperthreading, and the lower i3 processors didn't, that at least should have been done._


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## Vayra86 (Mar 1, 2018)

Even though I knew this and it IS super obvious if you know a bit of how things work under the hood, its nice to see the numbers.

Thanks

HT will always play second fiddle in performance, because it shares core resources and only works if those resources aren't saturated in any way. It also adds overhead that you don't get when threads run on a physical core.


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## dirtyferret (Mar 1, 2018)

I think typically the 6/6 wins out but the real issue is few Intel 4/8 & 6/6 are apples to apples as often the 4/8 are higher clocked like the 7700k to current 6/6 coffee lake like the 8400 or soon to be released 8500.  Obviously that will changed down the road.  

It really depends on the exact CPU options and their intended use but I love the tests you posted!


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## Deleted member 67555 (Mar 1, 2018)

I've always kind of looked at HT as a way to add an inch to your epeen.
However I would like to see compared with AMD as well even if just to see a 2% difference.
Thanks bro... Nice to see.


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## infrared (Mar 1, 2018)

Nice test @newtekie1


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## GoldenX (Mar 1, 2018)

Nice test, I would like to see the same methodology teste on a Ryzen, just to see the SMT scaling compared to HT.


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## newtekie1 (Mar 1, 2018)

dirtyferret said:


> I think typically the 6/6 wins out but the real issue is few Intel 4/8 & 6/6 are apples to apples as often the 4/8 are higher clocked like the 7700k to current 6/6 coffee lake like the 8400 or soon to be released 8500.  Obviously that will changed down the road.
> 
> It really depends on the exact CPU options and their intended use but I love the tests you posted!



Yeah, the clock speed is definitely a thing to consider, but I just wanted to show the affects of HT vs 2 extra cores.  Which is why I left the CPU clock the same.

Plus, the 7700k is clocked higher than the 8400 because they are two different product classes.  The 7700K was the high end aimed at enthusiasts processor, the 8400 is a mid-range that isn't aimed at enthusiasts.  A more accurate comparison would be between the i7-7700(non-k) and i5-8400.  In that case, the clock speed difference is only 200MHz, and I believe that difference will be 0 with the i5-8500 and the i5-8600(non-k) will actually be clocked 200MHz faster than the i7-7700.

And while I'd normally say that in this forum most of us are overclockers, so the 4C/8T processor might actually be a better overclocker and that is worth considering.  However, with Coffee Lake, it seems the 4C processors just aren't hitting the clock speeds the 6C processors are.  And maybe that points to a yield issue with the first batch of 4C Coffee Lake processors?  I don't konw.  That could very well be why HT was disabled on those processors in the first place, to improve yields, especially on the first run.



GoldenX said:


> Nice test, I would like to see the same methodology teste on a Ryzen, just to see the SMT scaling compared to HT.



If I had a Ryzen system to test with, I'd totally do it.

And now that I think about it, I really wish I would have done the test with 4C/4T too, to see exactly how much HT really adds.  I might just go back tonight and do that and update the chart.


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## dyonoctis (Mar 1, 2018)

My curiosity got the better from me and i've tried the cinebench, and the x265 test on a 1700x 4c/8T and 6c/6T. (same method of three run).

Cinebench :
6c/6T : 793
4c/8T : 757

x265 :
6c/6T :  24,30
4c/8T : 20,08

my sample might be too small, but i wasn't expecting a gap so small in cinebench. Meanwhile the scaling of SMT on x265 seems similar to HT, only better by roughly 3%.


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## Sasqui (Mar 1, 2018)

Huh...  I'm skeptical and think the Cache has something to do with it, but like you said, it shouldn't be *that* much!  Any way you can disable cache and test the same core configuration?  In any case... nice work @newtekie1


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## newtekie1 (Mar 1, 2018)

Sasqui said:


> Huh...  I'm skeptical and think the Cache has something to do with it, but like you said, it shouldn't be *that* much!  Any way you can disable cache and test the same core configuration?  In any case... nice work @newtekie1



Unfortunately, I don't know of any way to adjust the cache size.


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## mouacyk (Mar 1, 2018)

> Hyperthreading on 4 cores would equal 2 extra real cores


Well, you shut'em up for good.  HT performance is quite volatile, and really performs best where there are sufficieint memory or I/O stalls to take advantage of it.  I would never pick HT over real cores.


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## Vya Domus (Mar 1, 2018)

> Hyperthreading on 4 cores would equal 2 extra real cores. I've even see people here on the forums say this.



I got to say , that is some flawless logic.

They found the secret formula.


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## newtekie1 (Mar 3, 2018)

I updated the original post with 4C/4T results as well as adding in a single threaded test to the mix just to satisfy my curiosity.  I also added a second chart that show the actual percentage difference.


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## rtwjunkie (Mar 3, 2018)

Thanks for the update.  Hard numbers to sell support anecdotal knowledge most of us “knew” about single thread and HT is great!!


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## cucker tarlson (Mar 3, 2018)

You're spot on. 6c/6t > 4c/8t, though not by much. HT works really well on 4c CPUs.


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## HTC (Mar 3, 2018)

If i may make a suggestion to OP: have you considered doing these tests while there's something else running in the background? What exactly, i leave to you, but suggest you choose something that is a bit CPU / cache "heavy" while doing the tests mentioned in OP.

The purpose is to figure out how much, if any, is the performance hit. I'd expect the biggest hit will obviously go for the 4c/8t but, how much? That's the question!


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## newtekie1 (Mar 3, 2018)

HTC said:


> If i may make a suggestion to OP: have you considered doing these tests while there's something else running in the background? What exactly, i leave to you, but suggest you choose something that is a bit CPU / cache "heavy" while doing the tests mentioned in OP.
> 
> The purpose is to figure out how much, if any, is the performance hit. I'd expect the biggest hit will obviously go for the 4c/8t but, how much? That's the question!



I actually thought about this.  The problem was I couldn't come up with something that would run in the background that didn't just try to eat up all the CPU.  I thought about having a video encode running in the background, but that just loads the CPU to 100% by itself.  I couldn't really find anything that could consistently load down the CPU, but also was happy to share the CPU and didn't use the CPU to 100%.


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## cucker tarlson (Mar 3, 2018)

I'd be very interested in 6c/6t on DDR4 3000 vs 6c/12t on DDR4 2133.


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## FordGT90Concept (Mar 3, 2018)

It's always going to come down to the application.  If the application can saturate 12 logical processors, a 6c/12t processor is going to finish it faster than 6c/6t and any number of reduced cores.  If the application cannot then fewer, higher clocked logical processors will be faster.  Encoding falls in the former group; gaming usually falls in the latter group.



newtekie1 said:


> I actually thought about this.  The problem was I couldn't come up with something that would run in the background that didn't just try to eat up all the CPU.  I thought about having a video encode running in the background, but that just loads the CPU to 100% by itself.  I couldn't really find anything that could consistently load down the CPU, but also was happy to share the CPU and didn't use the CPU to 100%.


BOINC.  When you set it to "use at most 60%," it pulses the CPU so it only uses 60% of the available clocks by rapidly swapping between thread run and wait states.


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## newtekie1 (Mar 3, 2018)

FordGT90Concept said:


> It's always going to come down to the application. If the application can saturate 12 logical processors, a 6c/12t processor is going to finish it faster than 6c/6t and any number of reduced cores. If the application cannot then fewer, higher clocked logical processors will be faster. Encoding falls in the former group; gaming usually falls in the latter group.



Even then, with encoding it can come down to what you are encoding.  When I do encoding on my main rig, 720p and higher will use 100% of the CPU when doing x265 encoding.  But if I do DVD rip encodes at 480p it only uses between 60 and 80% of the CPU, it jumps around.



FordGT90Concept said:


> BOINC. When you set it to "use at most 60%," it pulses the CPU so it only uses 60% of the available clocks by rapidly swapping between thread run and wait states.



Yeah, that might work.  I was also thinking of F@H set to use half the available threds to keep the usage at 50%.  I might have to consider this later when I have more time to re-do all the tests.


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## HTC (Mar 3, 2018)

newtekie1 said:


> Even then, with encoding it can come down to what you are encoding.  When I do encoding on my main rig, 720p and higher will use 100% of the CPU when doing x265 encoding.  But if I do DVD rip encodes at 480p it only uses between 60 and 80% of the CPU, it jumps around.
> 
> 
> 
> Yeah, that might work.  I was also thinking of F@H set to use half the available threds to keep the usage at 50%.  *I might have to consider this later when I have more time to re-do all the tests*.



Suggest you pick one of the tests. Then, if the difference justifies it VS no program in the background, do the rest.


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## SamirD (Mar 7, 2018)

Very nice to see the numbers behind something like this.  My initial hunch was that the hyperthreading wouldn't help so much, but turns out that it does and that's why a 4c8t cpu is such a threat for a 6c6t in terms of marketshare.


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## newtekie1 (Mar 23, 2018)

SamirD said:


> Very nice to see the numbers behind something like this.  My initial hunch was that the hyperthreading wouldn't help so much, but turns out that it does and that's why a 4c8t cpu is such a threat for a 6c6t in terms of marketshare.



I really don't think the 4c/8t is close enough to the 6c/6t results to threaten it's marketshare.  There is still a pretty significant gap between the two.  If we assume the 4c/8t part was a little more expensive than the 8350k and cost about $200, the 8600k is $250 and I think the extra $50 is worth it if you do a lot of multi-threaded work.


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## Vario (Mar 23, 2018)

For the typical gamer type the 6 core 6 thread 8600K is perfectly adequate and should be for several years.  It also can clock very high.  Plenty of people on Overclock.net are in the 5.0Ghz+ range with it.


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## las (Mar 23, 2018)

Vario said:


> For the typical gamer type the 6 core 6 thread 8600K is perfectly adequate and should be for several years. It also can clock very high. Plenty of people on Overclock.net are in the 5.0Ghz+ range with it.



Pretty much all of those have delidded. 5.0 is easy with delid and proper paste - It can be archieved with very cheap air cooling. It's much harder and impossible on some without delid - This is why many settles with 4.7-4.8 GHz.

I've seen several 8700K's and 8600K's hit TJ MAX using 240-280mm AIO (H110's + H115i with PERFORMANCE preset + a few Noctua NH-D14/D15) ... Same CPU's did 5.2 and 5.3 after, with much much lower temps (around 75-85C avg load during burn in vs 100C+ aka throttling before)

This is how bad Intel's TIM is (the GAP does not help). USELESS for serious OC.

Delidding is a must if you want decent overclocks with good temps. Sad but true. Some people on this forum does not agree tho (LOL) ... Ask if Intel's TIM is good on overclock.net and see what people will say. 90% or more have delidded. And for good reason.


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## newtekie1 (Mar 23, 2018)

Vario said:


> For the typical gamer type the 6 core 6 thread 8600K is perfectly adequate and should be for several years.  It also can clock very high.  Plenty of people on Overclock.net are in the 5.0Ghz+ range with it.




A typical gamer should be fine with an 4c/4t processor.  The reality is, if you aren't doing a lot of multi-threading work, which games still really aren't, then a 3850K is still more than enough for gaming.



las said:


> Pretty much all of those have delidded. 5.0 is easy with delid and proper paste - It can be archieved with very cheap air cooling. It's much harder and impossible on some without delid - This is why many settles with 4.7-4.8 GHz.
> 
> I've seen several 8700K's and 8600K's hit TJ MAX using 240-280mm AIO (H110's + H115i with PERFORMANCE preset + a few Noctua NH-D14/D15) ... Same CPU's did 5.2 and 5.3 after, with much much lower temps (around 75-85C avg load during burn in vs 100C+ aka throttling before)
> 
> ...



I'm one that doesn't agree that Intel's TIM is bad.  From what I can tell they use some pretty good paste actually, the problem is the gap.

But the reality is, the difference between 4.8GHz and 5.2GHz is going to be negligible to most people that aren't going for benchmarking.  Even the theoretical performance increase is less than 10%, normal use isn't gong to show much difference.  And 99% of people will be happy at 4.8GHz.  No one _has_ to delid the processors, what they gain from it really isn't worth it despite how much overclockers like to whine about it.


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## Vario (Mar 23, 2018)

newtekie1 said:


> A typical gamer should be fine with an 4c/4t processor.  The reality is, if you aren't doing a lot of multi-threading work, which games still really aren't, then a 3850K is still more than enough for gaming.
> 
> 
> 
> ...


Agreed 100%.  I think it is the gap and the 100-200 mhz you might gain does not matter in the slightest.  Nor does the temperature reduction really matter, these processors can handle heat pretty well.


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## SamirD (Mar 26, 2018)

newtekie1 said:


> I really don't think the 4c/8t is close enough to the 6c/6t results to threaten it's marketshare.  There is still a pretty significant gap between the two.  If we assume the 4c/8t part was a little more expensive than the 8350k and cost about $200, the 8600k is $250 and I think the extra $50 is worth it if you do a lot of multi-threaded work.


It's interesting to hear you say that considering the graphs show a more significant gap between 4c8t and 4c4t than 6c6t.  In fact, aside from the Intel test, the 4c8t seems right on the 6c6t's heels in most applications--that is, unless I read the graphs wrong.


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## Hockster (Mar 26, 2018)

Supposedly Intel's choice of TIM is based on longevity and not pure thermal properties.


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## R-T-B (Mar 26, 2018)

Hockster said:


> Supposedly Intel's choice of TIM is based on longevity and not pure thermal properties.



I had a tube of the same "Dow Corning" stuff I suspect Intel uses.  It came with one of their "Extreme" heatsinks for LGA1366, one of their few tower style coolers.

The stuff was opened circa 2015 and was manufactered in 2012...

...and was pure, total, sand like powder in the package.  The syringe would barely push it out.

I have serious doubts about its longevity.  Hopefully it's not the same stuff, but I also have my doubts there.


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## jboydgolfer (Mar 26, 2018)

Vario said:


> For the typical gamer type the 6 core 6 thread 8600K is perfectly adequate and should be for several years.  It also can clock very high.  Plenty of people on Overclock.net are in the 5.0Ghz+ range with it.



I agree. I got mine into 5.2ghz, on aio with no prob right out of the box. Pretty much anyone gets them the basic close to 5ghz just as easy. Great chip.



newtekie1 said:


> what they gain from it really isn't worth it despite how much overclockers like to whine about it.


100% correct. i think the "i have nothing better to do than cry about it" comes out in the anal retentive "it should be perfect for what I want" people. Fact of the matter is, I will always trust that the Multi BILLION dollar/ year company has a bit more knowledge in what is or isnt right for a Good CPU over some nub on a PC site  who cries endlessly about how his CPU needed this or that to get it here or there. 

additionally:

it always blows my mind how blind a person can be, saying how this or that is wrong with a CPU, all while oblivious to how arrogant they come off thinking that a entire R&D team missed something while testing thousands of CPU's, that a single kid caught in his moms basement while testing his new CPU in a $800 PC which happens to be his 1st PC

One example of a miserable ocd grump.
Their not happy for the 40% they can overclock their new cpu....theyre pissed about the 2% they cant overclock it without preparations, & proper equipment.


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## Vayra86 (Mar 26, 2018)

SamirD said:


> It's interesting to hear you say that considering the graphs show a more significant gap between 4c8t and 4c4t than 6c6t.  In fact, aside from the Intel test, the 4c8t seems right on the 6c6t's heels in most applications--that is, unless I read the graphs wrong.



4c8t is right on 6c6t's heels in a 'best case scenario' where you actually use a workload that benefits from HT and is well threaded. In the most common use cases however, it falls down to being 'worth' about half a real core or fár less, up to the point of not having a benefit at all. For CPUs, a 25% performance drop is significant; that's more than the last three Intel gens combined.

6c6t on the other hand is 100% consistent in comparison. It'll do everything equally fast, alongside any number of other tasks. Also consider the marketplace where a 6c6t i5 is now available at same price as 4c8t of last gen.


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## jabbadap (Mar 26, 2018)

jboydgolfer said:


> I agree. I got mine into 5.2ghz, on aio with no prob right out of the box. Pretty much anyone gets them the basic close to 5ghz just as easy. Great chip.
> 
> 
> 100% correct. i think the "i have nothing better to do than cry about it" comes out in the anal retentive "it should be perfect for what I want" people. Fact of the matter is, I will always trust that the Multi BILLION dollar/ year company has a bit more knowledge in what is or isnt right for a Good CPU over some nub on a PC site  who cries endlessly about how his CPU needed this or that to get it here or there.
> ...



Are you using AVX offset? For fluidity one should use AVX stable clock speeds rather than maximum obtainable AVX offsets clock speeds...

On the topic though great work @newtekie1  . For the gametest you could make gtx1060 to not bottlenecking that much by running tests at 1080p at low settings or use 720p resolution. But when 6c/6t beats 4c/8t on all cpu intensive tests the gap will most probably just widen on games tests.


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## jboydgolfer (Mar 26, 2018)

jabbadap said:


> Are you using AVX offset? For fluidity one should use AVX stable clock speeds rather than maximum obtainable AVX offsets clock speeds...



I'm not at my PC so I'm going to have to go off of memory but off the top my head I'd say I have AVX set to auto .  It holds the overclock frequency even under sustained 100% load

I had to increase short duration and long duration a small amount but once I got it tuned in right (130 & 160 respectively) iirc , it held its clocks well. Set to offset +50,loadline1


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## Hayder_Master (Mar 26, 2018)

very nice work dear, i am asking your permission to share this awesome work on social media (i will translated to Arabic) and sure i will mention you name.


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## jabbadap (Mar 26, 2018)

jboydgolfer said:


> I'm not at my PC so I'm going to have to go off of memory but off the top my head I'd say I have AVX set to auto .  It holds the overclock frequency even under sustained 100% load
> 
> I had to increase short duration and long duration a small amount but once I got it tuned in right (130 & 160 respectively) iirc , it held its clocks well. Set to offset +50,loadline1



Yeah if it truly is 5.2GHz AVX stable, then you have won the silicon lottery. 

Asrock AVX auto offset can be 4 or 0 depending if Multi Core Enhancement is enabled or not. So pour some AVX load on it, if it drops to 4.8GHz all core then auto=4.


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## jboydgolfer (Mar 26, 2018)

Hayder_Master said:


> very nice work dear, i am asking your permission to share this awesome work on social media (i will translated to Arabic) and sure i will mention you name.



^^^^^^^^
@newtekie1 should get his attention in case he has thread notifications off.

https://www.techpowerup.com/forums/threads/4c-4t-vs-4c-8t-vs-6c-6t.241983/post-3819258


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## bug (Mar 26, 2018)

Meh, flamebait.

Everybody knows the choice of more cores vs more GHz is down to each users workflow.


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## dirtyferret (Mar 26, 2018)

The 8600k is "perfectly adequate" for gaming , looks like all those ryzen 1600 owners are screwed if they want more then adequate gaming performance...


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## jboydgolfer (Mar 26, 2018)

Any cpu made in the last few years with 4 or more cores is capable of great gaming, regardless of wether its intel of or amd. Any cpu feom the last 10 years with 4 or more cores is fine for gaming. Extra cores are great, but not required. Atleast thats my experience.


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## newtekie1 (Mar 26, 2018)

SamirD said:


> It's interesting to hear you say that considering the graphs show a more significant gap between 4c8t and 4c4t than 6c6t.  In fact, aside from the Intel test, the 4c8t seems right on the 6c6t's heels in most applications--that is, unless I read the graphs wrong.



15-20% is not right on the heels.



Hayder_Master said:


> very nice work dear, i am asking your permission to share this awesome work on social media (i will translated to Arabic) and sure i will mention you name.



Sure. As long as you credit me.


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## Bill_Bright (Jul 11, 2018)

I somehow missed this thread but I am glad dirtyferret pointed it out here. 
IMO, better late than never to say, excellent analysis! Well done newtekie1! 

I have to say I didn't learn anything new but that's fine because what this comparison did was (1) confirm what I already knew. But more importantly, it (2) explained in a very succinct and easy to understand manner how hyperthreading (HT) impacts performance on certain tasks. It also (3), gives insight to the difference between HT and the number of actual cores.

I would like to add one thing to the discussion. It should be remembered that Windows, the program itself, supports hyperthreading. What that means is when the OS is performing various housekeeping or other tasks (perhaps in the background), that is, when the OS is "multitasking" with a HT capable processor, the OS is likely able to complete some or all of those tasks more quickly. That in turn, frees up system resources more quickly - resources that can then be allocated to other tasks sooner, even towards tasks that do not support HT. 

Conclusion? Leave the defaults alone. That is, keep HT enabled. In the very rare scenario where HT might hinder performance, the impact is typically negligible and insignificant and only noticeable in benchmark tests, not in real world. The benefits for keeping it enabled, however, are often significant and very noticeable, depending on the tasks being being performed. 

As a side note,


newtekie1 said:


> I'm one that doesn't agree that Intel's TIM is bad. From what I can tell they use some pretty good paste actually, the problem is the gap.


I was so happy to see this comment. I cringe every time I see someone criticize OEM TIM from Intel or AMD. 

TIM is incredibly critical for thermal coupling and surely both Intel and AMD know and appreciate this. Yet it is incredibly inexpensive - especially in the quantities Intel and AMD use. Those thermal pads add barely a couple pennies to the cost of the CPU and heat sink fan assembly. Considering the cost vs benefits, it makes no sense for either company to supply OEM TIM that could not perform effectively. So they don't!

The most effective transfer of heat occurs with direct metal to metal contact so I also agree with newtekie1 that it is the gap that is the problem. That gap is inevitable when using "pads". *BUT* folks need to realize and remember that the bulk of those pads consists of purified "paraffin", typically a petroleum distillate very similar to kerosene. It takes a couple heat up and cool down cycles for that paraffin to thoroughly melt, spread out completely, then evaporate away to leave only the very thin layer of thermal interface materials behind. 

So unless you are doing extreme overclocking (and in that case, you should be buying a CPU that does not come with an OEM supplied cooler in the first place), give the OEM TIM a little time and a few heat up and cool down cycles to reach its peak effectiveness.


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## xorbe (Jul 11, 2018)

I can literally answer this from memory, having benchmarked compiling Liunx on 8086K very recently.  4C/8T HT is about 5C/5T at best.  Also, HT threading can suffer up to about 8% performance loss per thread compared to non-HT (this could be a variety of things, cpu or Linux scheduler).  6C/6T will beat 4C/8T in multi-threaded loads, it will be about 20% faster.


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## trparky (Jul 11, 2018)

I'm putting this post in this thread as versus the other thread that linked to this thread.


Vya Domus said:


> Basically under normal circumstances a core remains not fully utilized most of the time


Yes, very much so. Most of the time your processor core is doing nothing. It's tapping its virtual foot and saying "Hey, will someone give me something to do here. I'm bored!" Yes, this is true even in today's systems with SSDs because even though SSDs can deliver data faster than ever before your processor is still sitting around bored out of its silicon mind most of the time. Why? It has to do a lot with a great many things including branch prediction failures, cache misses, and various other situations that can result in performance bottlenecks. While a processor core is waiting for something (either because of a branch prediction failure or cache miss) that processor can't do anything; it's got to wait for whatever resources that it needs to continue doing work. Meanwhile that core is wasted. HT introduces the opportunity to run other tasks on that same core while the first "virtual" core is still waiting for whatever resources it needs to continue doing it's work.


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## Kissamies (Jul 11, 2018)

Went from 2c/2t (Pentium G4400) -> 2c/4t (Pentium G4560) -> 4c/4t (i5-7600K @ 4.7GHz) -> 4c/8t (i7-7700K @ 5GHz) 5c/10t (i7-5820K @ 4.5GHz with a defective core) and every step has given a nice boost.


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## Vayra86 (Jul 12, 2018)

Chloe Price said:


> Went from 2c/2t (Pentium G4400) -> 2c/4t (Pentium G4560) -> 4c/4t (i5-7600K @ 4.7GHz) -> 4c/8t (i7-7700K @ 5GHz) 5c/10t (i7-5820K @ 4.5GHz with a defective core) and every step has given a nice boost.



Absolutely, the key is always in timing vs. the applications you use. And more is always better until its too much


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## GorbazTheDragon (Jul 13, 2018)

Surprised you didn't answer the original question of whether the 4/8 would cannibalise the 6/6 market, I think the answer would definitely be yes.

The thing it comes down to is that an unlocked 4/8 cpu would be able to more than match stuff like the 8400 and other mid/low clocked 6/6 chips.

If the new Xeon E3s 4/8s are well priced they could be a good alternative to the i3 and i5 4/4s and 6/6s.


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## Melvis (Jul 13, 2018)

For those people that want to know about Gaming results with cores disabled etc etc


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## xorbe (Jul 13, 2018)

The only reason SMT disabled is pushed as an SKU is to prop up prices of SMT enabled parts.


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## Totally (Jul 13, 2018)

newtekie1 said:


> Stuff


 If you throw out the Intel burn test and cinebench, all the 4c/8t and 6c/6t results are within 15% (13% at widest, 6% at narrowest) of each other. We your co-worker was saying has merit as going from 4c/8t to 6c/6t doesn't yield enough benefit to justify it.


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## newtekie1 (Jul 14, 2018)

I'm thinking of redoing these tests, but adding in the 6c/12t, as well as doing a few game tests.  I'm thinking GTA:V, Cities Skylines, and FarCry5.



Totally said:


> If you throw out the Intel burn test and cinebench, all the 4c/8t and 6c/6t results are within 15% (13% at widest, 6% at narrowest) of each other. We your co-worker was saying has merit as going from 4c/8t to 6c/6t doesn't yield enough benefit to justify it.



In the end it is going to come down to pricing to determine if it was worth it or not.  If we only look at K series skus, the 8350k is $185 and the 8600K is $245, that already is only a $60 price difference.  If the 4c/8t part was priced somewhere in the middle of those two processors, then it wouldn't be worth it at all, spend the extra ~$30 and get the 8600k(frankly, spend the extra $60 and get the 8600k over the 8350k).  Even if the 8350k was released as a 4c/8t part, at the same $185 price point, IMO it is a hard sell to save the $60 over an 8600k.


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## GorbazTheDragon (Jul 14, 2018)

I wonder what intel will do in the future? 8/16 i7s, 6/12 i5s, and 4/8 i3s?

Maybe they will want to have some 8/8 and 6/6 chips at lower cost to be able to sustain sensible production rates for those dies, but considering the market share of the 8700k is substantial compared to the 8600k and 8400, i would not have expected this to be a problem.


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## SamirD (Jul 14, 2018)

GorbazTheDragon said:


> I wonder what intel will do in the future? 8/16 i7s, 6/12 i5s, and 4/8 i3s?
> 
> Maybe they will want to have some 8/8 and 6/6 chips at lower cost to be able to sustain sensible production rates for those dies, but considering the market share of the 8700k is substantial compared to the 8600k and 8400, i would not have expected this to be a problem.


I would look at the xeon line to see what the roadmap might look like.  It's no secret that a lot of the desktop chips share a lot with their server/workstation brethren.


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## Bill_Bright (Jul 14, 2018)

newtekie1 said:


> I'm thinking of redoing these tests, but adding in the 6c/12t, as well as doing a few game tests. I'm thinking GTA:V, Cities Skylines, and FarCry5.


The more variety and number of "samples" you include will indeed make the results more realistic. But to be realistic, there should be tests other than games too. Compiling huge data bases, for example. 

But frankly, I think you have already proved the point nicely. To be any more useful to someone, your test would have to based specifically on that user's specific system, and the specific tasks (programs) he or she will be running. 

I'm going back to what I said earlier. Windows knows how to use HT. And since Windows can complete its own tasks quicker by using HT, that's better for "over all" system performance. So IMO, if the budget allows, that's reason enough to spring for a CPU that supports it.


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