Personally, I would not want my CPU core temperatures to exceed 75C.

Mine runs at 75 in RealBench and of course much lower than that in everyday use. 

 

I wouldn't have an issue at 85 in Real Bench to be honest. 

 

Greater than 85 instability can rear it's ugly head.

Personally, I would not want my CPU core temperates to exceed 75C.

 

 

Depends on when it does. I did some stresstests when I got my current PC and temps were all over 90 but in every day use it never ever gets near to that. If you survive a stresstest, even on the limit, you can go ahead and use the OC for every day use (including flightsimming) without any problems. Well, anyway, that is my experience. No guarantees LOL

I did some stresstests when I got my current PC and temps were all over 90 

 

 

 

That was probably running AVX. Which pretty much none of us encounter in daily use. Not unless you happen to be running Adobe Premier, some aspects of Photoshop etc.

 

I'm at 75 in Realbench, but I bet if I ran Prime95 with AVX I'be be much higher. Prime is vicious these days. I avoid it.

 

Edit: 

 

Yep, just ran Prime95 Small FFT. Hit 95 degrees in no time. Yikes!

 

So yes, "some" stress tests will exceed 90 degrees. But it's the AVX instruction sets that's the issue, and in particular the  vicious nature of Prime 95 Small FFT's.

What is AVX?

What is AVX?

 

 

AVX Instruction Sets. Advanced Vector Extensions. Extensions to the X86 instruction sets. Trouble is that in adaptive voltage mode, or offset mode, the CPU will boost it's voltage to accommodate AVX. Particularly AVX 2.

 

That means that what would ordinarily be a safe, cool overclock, suddenly stats hitting high temps. Like my example above with Small FFT's in Prime.

 

This is why the advice is to take care with adaptive or offset voltage. When we overclock, we should take into consideration if we will be running synthetic stress tests that run AVX. If we won't be, we can overclock higher with higher voltage. In fact Asus Five Way Optimisation, auto overclocking, includes a tick box for this very reason.

 

My advice is to overclock higher and don't run synthetic stress tests that include AVX. As I said, most of us never encounter AVX in daily use. If you feel you must run Prime, then just run the blend test. 

 

The new Kaby Lake CPU's and actually Broadwell, include an AVX offset mode. it will lower the voltage and frequency automatically if it detects you are running an applications that runs AVX... great stuff! So you can run at lets say 5 Ghz, but if you run a stress test with AVX, it drops it to whatever you set the offset to in the BIOS.

Interesting..I'm also in the process of optimizing my 7700K overclock. Using AVX at -2 I was -5C max temp, but still in the 86. Indeed temps are very dependable on Vcore. 

 

AVX Instruction Sets. Advanced Vector Extensions. Extensions to the X86 instruction sets. Trouble is that in adaptive voltage mode, or offset mode, the CPU will boost it's voltage to accommodate AVX. Particularly AVX 2.

 

That means that what would ordinarily be a safe, cool overclock, suddenly stats hitting high temps. Like my example above with Small FFT's in Prime.

 

This is why the advice is to take care with adaptive or offset voltage. When we overclock, we should take into consideration if we will be running synthetic stress tests that run AVX. If we won't be, we can overclock higher with higher voltage. In fact Asus Five Way Optimisation, auto overclocking, includes a tick box for this very reason.

 

My advice is to overclock higher and don't run synthetic stress tests that include AVX. As I said, most of us never encounter AVX in daily use.

 

The new Kaby Lake CPU's and actually Broadwell, include an AVX offset mode. it will lower the voltage and frequency automatically if it detects you are running an applications that runs AVX... great stuff! So you can run at lets say 5 Ghz, but if you run a stress test with AVX, it drops it to whatever you set the offset to in the BIOS.

 

Martin, what AVX offset you use typically for a 5Ghz overclock? Also, which benchmark you suggest that don't use AVX? I find XTU achieves less max temp than RealBench.

Great Work Martin, thanks

Hope that you had a nice birthday, congrats

 

Avx offset 2-4 you can have it up to the point where you feel comfortable with the temps

If you run 5.0ghz put 10 it clock down to 4.0ghz when feel Avx.

Martin, what AVX offset you use typically for a 5Ghz overclock? Also, which benchmark you suggest that don't use AVX? I find XTU achieves less max temp than RealBench.

 

 

 

AVX offset isn't applicable to me. I have a 6700K Skylake which doesn't have the facility for an AVX offset. 

 

As you can see from my run with Prime Small FFT's above, I quickly hit 95 degrees. Not far from the CPU throttling back. TJMax is 100C.

 

I only use RealBench these days. I believe RealBench does run AVX, but I don't think it runs AVX 2, AVX2 is the main issue.  

 

The point is, stress tests that run AVX are not created equally. I can run Aida64 with FPU, so AVX, and the temp isn't too bad, I can run RealBench and not exceed 75... but Prime is a different story.

 

What are you hitting in RealBench now?

Hope that you had a nice birthday, congrats

 

 

 

 

Thanks Hasse.  :smile:

 

Do you know if RealBench runs AVX? I believe it does. Pretty sure it doesn't run AVX 2 though.

In the Benchmark you have small bursts of avx in encoding and heavy multitasking ( test 2 and 4 )

Seems not to be any in the stresstest

Thanks Hasse.

I have a weird observation. Below is an XTU plot of a flight from Fly Tampa Sydney on the PMDG T7 from the gate to cruise. At 5 Ghz, AVX at -5 and 1.37 Vcore. The XTU maximum temperature is 89C while most of the time the temperatures are below 75C. Using CPUID on the same time, the max temp reported is 96C and using Real Temp, it is 90C. Which to believe?
 

 

 

 

 

Not too bad

 

 

Temps don't kill.....voltage kills.

Hard for me to explain in eng.

96c is pagage ( think Martin can explain )

The core temps is pretty close

sounds like these chips arent worth the upgrade coming from 6600/6700k. Im really looking forward to the amd ryzen and see what it can do.