# Prime95 vs. Linpack Xtreme



## Regeneration (Oct 27, 2018)

The video above demonstrates the superiority of Linpack Xtreme versus the latest version of Prime95. The overclocked PC passed nearly 2 hours of Prime95's small FFTs torture test and yet completely crashed within less than a minute and a half with the bootable version of Linpack Xtreme integrated on Porteus Linux.

Computer specifications: Intel Xeon W3680 @ 4.17 GHz (144x29), ASUS P6T (vanilla), 3x 4GB G.Skill Ares F3 @ 2304 MHz (10-12-12-31 CR1), and Nvidia GeForce GTX 970.


----------



## Batou1986 (Oct 28, 2018)

I have been trying to tell people for years prime is not enough to stress a modern CPU for years but they wont listen.


----------



## Regeneration (Oct 28, 2018)

It took 77 seconds for Linpack to hard lock the entire system


----------



## steen (Oct 28, 2018)

You've got interesting ratios for a W3680. Is that just a max stable for P95? Mine are OEM so 4GHz 133x30 & 3x4GB 1333 ECC is P95/Linpack stable. Bclk >138MHz results in instahang. They've been running the last 4 years @ 3.8GHz all core turbo. With decent motherboards I'd be running bclk 166x25 & 1866 DDR3.


----------



## Regeneration (Oct 28, 2018)

steen said:


> You've got interesting ratios for a W3680. Is that just a max stable for P95? Mine are OEM so 4GHz 133x30 & 3x4GB 1333 ECC is P95/Linpack stable. Bclk >138MHz results in instahang. They've been running the last 4 years @ 3.8GHz all core turbo. With decent motherboards I'd be running bclk 166x25 & 1866 DDR3.



Max stable for Linux.


----------



## Space Lynx (Oct 28, 2018)

no offense but prime95 load is unrealistic for 90% of us gamers, so its stable enough for us.


----------



## Regeneration (Oct 28, 2018)

lynx29 said:


> no offense but prime95 load is unrealistic for 90% of us gamers, so its stable enough for us.



There is no such thing as 'unrealistic load'.

Computers were originally created to solve equations. And that's what Prime95 and Linpack do, just in a larger scale and for longer periods.

Even basic features like 'Windows Update' need to solve equations, check checksums, etc. Not to mention plenty of 3rd party apps, and even games' DRM.


----------



## hat (Oct 28, 2018)

Could you run the Windows version of Linpack Xtreme and see how it stacks up against the bootable Linux version?


----------



## Regeneration (Oct 28, 2018)

hat said:


> Could you run the Windows version of Linpack Xtreme and see how it stacks up against the bootable Linux version?



Linux crashes a lot faster (300%) than Windows due to the balanced load distribution across both physical and virtual cores.


----------



## hat (Oct 28, 2018)

But shouldn't it be 100% load? 100% should be 100%, and load distribution shouldn't really come into play in such a situation... unless I'm sorely mistaken. I'll take your word for it, just curious of the mechanics. Does it also find unstable memory faster under Linux?


----------



## Regeneration (Oct 28, 2018)

Linux treats all cores as physical.
Windows prioritizes physical over virtual cores.

And yes, unstable memory crashes faster on Linux as well.


----------



## Mussels (Oct 28, 2018)

we need a torture test linux build with CPU GPU and ram stress tests built in


----------



## kastriot (Oct 28, 2018)

If oc-ed system in windows passes prime for 12-24 hours and intelburn 128 passes @Extreme it means it's perfectly stable for 99.99% people who mostly play games or whatever and for people who use PC for bussines or science they do NOT oc their PC, so this test is practically useless because 99.9% use windows here.


----------



## Vayra86 (Oct 28, 2018)

lynx29 said:


> no offense but prime95 load is unrealistic for 90% of us gamers, so its stable enough for us.



Speak for yourself, that whole argument is complete BS and you know it. This topic is about the fact that even Prime isn't really a nasty load to put on a CPU these days. Go figure. A CPU can't even do a mild stress test (but it can run 5+ Ghz in idle or with 10% load! yay!) and 'gamurs' call it a proper OC...

Skipping tests because your CPU is cooking due to it is a clear sign you should be backing off. Instability is a clear sign you should be backing off. Anything else and you're deluding yourself.

Linpack was always a pretty good test to run for stability, glad to see it hasn't changed


----------



## Space Lynx (Oct 28, 2018)

Vayra86 said:


> Speak for yourself, that whole argument is complete BS and you know it. This topic is about the fact that even Prime isn't really a nasty load to put on a CPU these days. Go figure. A CPU can't even do a mild stress test (but it can run 5+ Ghz in idle or with 10% load! yay!) and 'gamurs' call it a proper OC...
> 
> Skipping tests because your CPU is cooking due to it is a clear sign you should be backing off. Instability is a clear sign you should be backing off. Anything else and you're deluding yourself.
> 
> Linpack was always a pretty good test to run for stability, glad to see it hasn't changed




hmmm well speak for yourselves, my old PC failed Prime95 Small FFT all the time, but I could still run 10 hour plus gaming marathon sessions with 0 issues and 0 downclocking.  /shrug


----------



## Vya Domus (Oct 28, 2018)

Each to their own, if you wish to stress your PC for days on end with absurdly intensive tests by all means go ahead. Just so you know, no matter how absurd the test is, it still can't possibly cover all instruction combinations and whatnot therefore a window for instability *will always be there*. If you think that you are definitely safe after you do all that then you are just as disillusioned.

Testing for stuff that is outside your use case it's simply useless, sure it may make you sleep better at night knowing that but it's still useless nonetheless. Even Intel or AMD had cases where they shipped CPUs that were unstable under specific situations and most CPUs today likely still have weaknesses like that buried deep inside obscure instruction combinations.

I'll stick with something like AIDA64 FPU test, perfectly reasonable. I am not launching satellites into space and calculating trajectories and neither are most of you. But like I said, whatever floats your boat.


----------



## Mussels (Oct 28, 2018)

some of us dont want to risk crashes or issues ever, others are willing to.

Those who dont fully test their systems are the same ones who come crawling to the forums asking for help, because this one specific game/program crashes and not the others, or they corrupted a hard drive and need data saved...


----------



## Space Lynx (Oct 28, 2018)

Mussels said:


> some of us dont want to risk crashes or issues ever, others are willing to.
> 
> Those who dont fully test their systems are the same ones who come crawling to the forums asking for help, because this one specific game/program crashes and not the others, or they corrupted a hard drive and need data saved...



very subjective and generalised statement, but sure.


----------



## Regeneration (Oct 28, 2018)

lynx29 said:


> hmmm well speak for yourselves, my old PC failed Prime95 Small FFT all the time, but I could still run 10 hour plus gaming marathon sessions with 0 issues and 0 downclocking.  /shrug



There was a version of Prime95 that crashed on AMD Phenom II CPUs for absolutely no reason. Took me days to figure it out.


----------



## er557 (Oct 28, 2018)

Ok, just ran it, the default test passed fine, also then ran a 35000 problem size test, about most of it ran fine, while heating up to 89c, which is uncomfortable for me,
the results were 653 gflops,
nonetheless, when I also browsed the internet with firefox during the test, the pc rebooted, so I chalk it up to kernel instability or something gpu related, as standalone the console window ran fine.
Also, it didn't properly detect 36 cores, 72 threads, as didn't the sensors console.
Temps for both cpu's in the tray detected fine.
Specs: Non overclocked dual xeon e5 2686 v3, with hacked turbo @72 threads @3.5ghz, undervolted core , cache, and system agent(-80,-50,-50), with microcode 0x39 loaded on boot.


----------



## EarthDog (Oct 28, 2018)

Vya Domus said:


> Each to their own, if you wish to stress your PC for days on end with absurdly intensive tests by all means go ahead. Just so you know, no matter how absurd the test is, it still can't possibly cover all instruction combinations and whatnot therefore a window for instability *will always be there*. If you think that you are definitely safe after you do all that then you are just as disillusioned.
> 
> Testing for stuff that is outside your use case it's simply useless, sure it may make you sleep better at night knowing that but it's still useless nonetheless. Even Intel or AMD had cases where they shipped CPUs that were unstable under specific situations and most CPUs today likely still have weaknesses like that buried deep inside obscure instruction combinations.
> 
> I'll stick with something like AIDA64 FPU test, perfectly reasonable. I am not launching satellites into space and calculating trajectories and neither are most of you. But like I said, whatever floats your boat.


+1.

P95, using a combo of small fft and blend (using versions with avx/fma/etc), is fine for plenty. More is overkill. Aida64 stress test + fpu only stresses my system fine. When I say fine, I say it passes for at least 6 hours (ea test). For how I use my PC, mostly gaming, photoshop editing, some encoding, works a charm. THAT, gents, is stable and can be found with existing applications. 

Something more stressful than p95 is like running furmark on a gpu.... a power virus and overkill. And for gpus, just plain dumb.

Thanks but... no thanks. No need for users to go to this level.


----------



## er557 (Oct 28, 2018)

I think the Linux kernel is less protected or isolated than windows , which is why stress tests don't crash there. It's indeed an extreme use case scenario, it's like I don't test my car on the Monaco grand prix, rather on the city streets.


----------



## Regeneration (Oct 28, 2018)

er557 said:


> I think the Linux kernel is less protected or isolated than windows , which is why stress tests don't crash there. It's indeed an extreme use case scenario, it's like I don't test my car on the Monaco grand prix, rather on the city streets.



Professional mechanics use computer and a special garage environment to test cars.

Some hardware components use Linux to update firmware. You surely don't want your SSD firmware update to fail in the middle because of OC instability.

Hardware failures on Linux usually crash the entire system (kernel panic). That reboot you mentioned, probably had nothing to do with the GPU.

If the CPU runs fine on Linux with stock clocks, it should run fine even when overclocked.


----------



## Vayra86 (Oct 28, 2018)

Mussels said:


> some of us dont want to risk crashes or issues ever, others are willing to.
> 
> Those who dont fully test their systems are the same ones who come crawling to the forums asking for help, because this one specific game/program crashes and not the others, or they corrupted a hard drive and need data saved...



Amen to this.

When my rig crashes, I simply know for a fact the overclock is not the issue. I can then analyze the problem for what it is without having to reproduce it on stock settings.

That said everyone should do things however they like, I just think its wrong to defend a half-assed overclocking practice as a great way to do it. Its really not - the benefit of that extra 100 mhz doesn't ever really pay off anyway in meaningful performance, but the instability is a pain in the behind and can even cost you money when it happens at unfortunate times. And (my) experience tells me: its *always* an unfortunate moment.


----------



## SIGSEGV (Oct 28, 2018)

For me, personally, prefer to use 3DMark and gaming that use a high load of resources to test the system stability.  Do the test for 2 - 3 loop (spy, firestrike ultra or combination) and gaming for the rest.


----------



## Regeneration (Oct 28, 2018)

I built a i7-965 system 10 years ago, and every few months, I was getting "one of your disks needs to be checked for consistency" message followed with data corruption.

That system passed 48 hours of Prime95, so I replaced the HDD, with no luck. I spent months replacing other parts.

Took me 2 years to determine the issue caused by overclocking and vdroop. This is when I adopted Linpack for the first time.

I stress test each overclocked component separately for 12 hours. No suprises ever since.


----------



## EarthDog (Oct 28, 2018)

You could have figured that out by going back to stock your overclock isnt stable. You cant rely on ONE thing be it P95, Linpack libraries, whatever. A little common sense goes a long way. One doesn't have to pump and even more difficult and unrealistic load on the cpu to figure things out. 

Again, to each their own... I know I dont need more than A64 stress and its fpu only test to figure out I'm stable. Few want or need more though. I just dont see a point in turning up the heat for what amounts to most as no reason.


----------



## hat (Oct 29, 2018)

So, first you



EarthDog said:


> You cant rely on ONE thing be it P95, Linpack libraries, whatever



But then



EarthDog said:


> Again, to each their own... I know I dont need more than A64 stress and its fpu only test to figure out I'm stable. Few want or need more though. I just dont see a point in turning up the heat for what amounts to most as no reason.



Wat

Anyways, I come from the camp that says you need serious stress testing before you call a rig "stable". Prime95 is _part_ of that for me, but so is Linpack. OCCT is another good one. There were many debates across the web about whether Prime95 or OCCT was better... many people on either side of the fence. The only way to be sure is to try 'em all... and something else may _still_ crash. There are no 100% guarantees, but a proper suite of different tests is the best you can do.


----------



## R-T-B (Oct 29, 2018)

lynx29 said:


> no offense but prime95 load is unrealistic for 90% of us gamers, so its stable enough for us.



Unstable is unstable.  There is no real "stable for select workloads."  It's either stable or it isn't.  If it isn't, one day you will find out (and hopefully not during a raid like our own @W1zzard)


----------



## Space Lynx (Oct 29, 2018)

R-T-B said:


> Unstable is unstable.  There is no real "stable for select workloads."  It's either stable or it isn't.  If it isn't, one day you will find out (and hopefully not during a raid like our own @W1zzard)



your 8700k at AVX offset 0 at 5ghz doesn't have a single core or thread fail on prime95 small fft for 12+ hours? i find that hard to believe


----------



## EarthDog (Oct 29, 2018)

hat said:


> So, first you
> 
> 
> 
> ...


If taking things out of context needed defined... lolol!


To be more clear, if you want the kind of unwavering stability the OP or those like him want, users cant use one type of test.

I dont have anything critical that takes hours days or weeks to crunch. I can do what do, leave it up for days gaming for hours on end, and it doesn't flinch. One app. Hopefully that clarifies things.



R-T-B said:


> Unstable is unstable.  There is no real "stable for select workloads."  It's either stable or it isn't.  If it isn't, one day you will find out (and hopefully not during a raid like our own @W1zzard)


sure there can be. Everyone's stable is something different, right? What if it's just a internet email web game PC? A hardcore gaming PC? Something that crunches avx for a week? I can be stable for 'my' uses (meaning it doesn't crash in me) but those same settings aren't stable for the dude pounding avx data. You can belt out that really isnt stable, but its who's holding the bar as to how stable is defined. If a tree falls in the forest.....


----------



## MrGenius (Oct 29, 2018)

EarthDog said:


> If a tree falls in the forest.....


...and lands on a bear taking a shit. Does it make a sound?

a) The bear does.

b) The tree does.

c) Both do.

d) Bears don't shit in the woods.

e) None of the above.


----------



## Regeneration (Oct 31, 2018)

A user on 3DCenter forums posted a comparison of Linpack Xtreme vs. other stress tests on i7 8700K.






And that's with the Windows version, which is a bit inferior to the Linux version.


----------



## EarthDog (Oct 31, 2018)

This shows what... that it is just as hard as the others? That is what I take away from this post. 

EDIT: Whoever did this should have closed out the damn program and start new for each test so that the maximum actually shows for each instead of looking at the current values which can be anything at any time. Thoough......... not sure the point here, we believed you, most just don't give a hoot to test this thoroughly and don't have a need.


----------



## baryluk (Nov 4, 2018)

Just some data for you comparing mprime / Prime 95, and Linpack Xtreme. Update: y-cruncher too.


----------



## R-T-B (Nov 4, 2018)

lynx29 said:


> your 8700k at AVX offset 0 at 5ghz doesn't have a single core or thread fail on prime95 small fft for 12+ hours? i find that hard to believe



I don't.  I know I'm stable.  1.35v required though, which makes a lot of heat.  I can pass 24 hours in my rig at most ambients up to 95F+ with the following aproach I have used for quite some time.

1.) Run 3000RPM blower fans.   2.)  Run extension cables and stay far away.


----------



## Space Lynx (Nov 4, 2018)

R-T-B said:


> I don't.  I know I'm stable.  1.35v required though, which makes a lot of heat.  I can pass 24 hours in my rig at most ambients up to 95F+ with the following aproach I have used for quite some time.
> 
> 1.) Run 3000RPM blower fans.   2.)  Run extension cables and stay far away.



that really is a golden chip I sold you, I had another 8700k after that one and and 8600k, even at stock voltage stock everything, it would fail on one thread on prime95 small fft. ended up refunding it. the 8600k did work for the most part, but it would always have one thread fail no matter the oc or voltage, i tried 4.9 all 6 cores, 1.38v 1.32v, temps were good, etc etc just no luck.


----------



## whitepuzzle (Jul 25, 2019)

As I see it, unstable is unstable. Computers are equation solving machines -- if the machine fails to solve every equation correctly with integrity, it is unstable and the overclock is bogus. I agree with "there is no such thing as gaming stable".

Better to have rock stable 4.9GHz than faff about with a silly 5.0GHz overclock that might maybe possibly perhaps won't crash under  gaming load but under the hood is objectively erroneous 

With that said, I question the alleged total superiority of Linpack. I was just testing an OC on my 8350K which made it through 8 hours of LinpackXtreme, then crashed in 10 minutes of Large FFT in P95. Confirmed that it was indeed the core clock (and not memory, as expected from Large FFT) causing the instability as when dialed back to previously known stable configuration, errors in Large FFT disappeared.

Perhaps a combination of Linpack and P95 is the ultimate form of overclock verification. All the other softwares such as Aida and OCCT appear overly commercial and unpalatable to my taste anyhow.


----------



## Space Lynx (Jul 25, 2019)

whitepuzzle said:


> As I see it, unstable is unstable. Computers are equation solving machines -- if the machine fails to solve every equation correctly with integrity, it is unstable and the overclock is bogus. I agree with "there is no such thing as gaming stable".
> 
> Better to have rock stable 4.9GHz than faff about with a silly 5.0GHz overclock that might maybe possibly perhaps won't crash under  gaming load but under the hood is objectively erroneous
> 
> ...



you need to learn how to power up your tech homie. 5ghz or go home for this crew


----------

