Temps are much higher with the newest version of P95 than LinX???

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beekermartin

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I ran the newest version of P95 tonight and two cores hit 80c! When I run LinX the hottest core hit 65c.

I am installing a custom water cooled loop soon so I don't want to discuss my exact temps or setup. I am just curious why P95 was hitting much higher temps than LinX. I don't remember P95 having higher temps than LinX.

Is the newest P95 different than older version?
 
Solution
CompuTronix
beekermartin,

Do NOT run any versions of Prime95 later than 26.6. Here's why:

Core i 2nd through 6th Generation CPU's have AVX (Advanced Vector Extension) instruction sets. Recent versions of Prime95, such as 28.9, run AVX code on the Floating Point Unit (FPU) math coprocessor, which produces unrealistically high temperatures. The FPU test in the utility AIDA64 shows similar results.

Prime95 v26.6 produces temperatures on 3rd through 6th Generation processors more consistent with 2nd Generation, which also have AVX instructions, but do not suffer from thermal extremes due to having a soldered Integrated Heat Spreader and a significantly larger Die.

Please download Prime95 version 26.6 -...
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CompuTronix

CompuTronix

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beekermartin,

Do NOT run any versions of Prime95 later than 26.6. Here's why:

Core i 2nd through 6th Generation CPU's have AVX (Advanced Vector Extension) instruction sets. Recent versions of Prime95, such as 28.9, run AVX code on the Floating Point Unit (FPU) math coprocessor, which produces unrealistically high temperatures. The FPU test in the utility AIDA64 shows similar results.

Prime95 v26.6 produces temperatures on 3rd through 6th Generation processors more consistent with 2nd Generation, which also have AVX instructions, but do not suffer from thermal extremes due to having a soldered Integrated Heat Spreader and a significantly larger Die.

Please download Prime95 version 26.6 - http://windows-downloads-center.blogspot.com/2011/04/prime95-266.html

Run only Small FFT’s for 10 minutes.

Use Core Temp to measure your temperatures - http://www.alcpu.com/CoreTemp

Your Core temperatures will test 10 to 20C lower with v26.6 than with v28.9.

Also, you might want to read this Sticky: Intel Temperature Guide - http://www.tomshardware.com/forum/id-1800828/intel-temperature-guide.html

CT :sol:
 
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beekermartin

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Thank you Computronix. That makes a lot of sense. My CPU temps never pass 70c no matter how many hours of gaming. I was shocked to see the newest version of P95 breaking 80 with LinX only hitting mid 60s. I will download 26.6 and retest. Thanks!
 
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beekermartin

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I just realized I have asked this question before but totally forget. I googled only using P95 26.6 and my original thread popped up. Computronix gave me the response then. Sorry for wasting everyone's time. Thanks again computronix.
 
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beekermartin

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I ran P95 26.6 at the same 1.10 volts that I was stable with when I built this system and sure enough it passed for over 3.5 hours. I also ran IBT and LinX at the max settings and it passed those as well. But if I try using the newest version of P95 it crashes almost immediately.

So I guess I am still stable but I am still curious why the newest version of P95 is not.
 
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CompuTronix

CompuTronix

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Since the newer versions of Prime95 after version 26.6 run AVX / AVX2 / FMA3 code on the FPU within the CPU, higher Vcore is required (which causes higher Core temperatures) to remain stable. If your Vcore is fixed at 1.1 and Prime95 version 26.6 is stable, then of course you can expect that Prime95 version 28.9 will crash without additional Vcore.
 
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beekermartin

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So if I was able to pass p95 26.6, IBT and LinX that I am stable? I understand the newer version of P95 require more vcore because of how it stresses the FPU. Are there any real world situations that could stress the cpu in a similar manner causing it to be unstable?
 
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CompuTronix

CompuTronix

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AVX is used in transcoding. RealBench provides a realistic AVX workload to stress test your CPU: Asus RealBench - http://rog.asus.com/15852014/overclocking/realbench-v2-4-launched-with-x99-support/

RealBench will not cause unrealistic Core temperatures.
 
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