Overclock with avx.

[p00kie]

So my I7 7700K is able to run at 5ghz on 1.256v.(voltage was set to 1.235 with adaptive mod)

Now it passes every single stress test i did on it(realbench,cinebench r15 20 runs,intel burn test,ada64,even rendering a real video that took around 30 mins to render).EXCEPT prime95 which gives me error messages if not in instant then after a minute or 2.Temps are fine (around 55 max 62)

Now i found a "fix" for this issue and that is avx offset that clocks my cpu down to 4.7 which makes it stable on prime95.so im not sure if its okay to let it be like that.or should i up the voltage.

 

[volkgren]

We usually test with Prime95 v26.6 to avoid using AVX. But AVX offset is good if you need it.

 

[Barty1884]

Do you actually use the system for any AVX workloads? Some Adobe products, compression, codecs etc?
If you have AVX workloads, you'd probably know.

So, if you do then you have to decide if you want to try to push the higher clocks for AVX or not. If you're comfortable at 4.7Ghz, then the offset is fine.
Similarly, if you don't use it.... then it doesn't really matter that it's at 4.7, and you'd be better maintaining the lower voltage than pushing for AVX clocks you'll never use.

 

[p00kie]

Do you actually use the system for any AVX workloads? Some Adobe products, compression, codecs etc?
If you have AVX workloads, you'd probably know.

So, if you do then you have to decide if you want to try to push the higher clocks for AVX or not. If you're comfortable at 4.7Ghz, then the offset is fine.
Similarly, if you don't use it.... then it doesn't really matter that it's at 4.7, and you'd be better maintaining the lower voltage than pushing for AVX clocks you'll never use.

No I don`t use my pc for AVX workloads.my target is ingame FPS but i want in the same time stable pc that will be able sometimes to encode a video that i have recorded with nvidia shadowplay.(Im not worried about encoding speed ) Im worried if something else can "crash" a pc...

 

[p00kie]

We usually test with Prime95 v26.6 to avoid using AVX. But AVX offset is good if you need it.

Its the only thing "crashing" (erros messages popingout) my pc.Is there anything else except AVX codes that can stress the system this much? or am i "crash free" if i leave overclock at 5.0ghz and AVX offset on 3..Since im using pc mostly for gaming SOMETIMES for encoding a video that i recorded with nvidia shadowplay.

 

[CompuTronix]

... 7700K ...5ghz on 1.256v.(voltage was set to 1.235 with adaptive mod) ... passes every single stress test ... EXCEPT prime95 ... Temps are fine (around 55 max 62) ... avx offset ... makes it stable on prime95 ...

p00kie,

What is your ambient temperature?

Although you said "Temps are fine (around 55 max 62)", I take that to mean Prime95 (AVX) version 29.4 Small FFT's with AVX offset at 3. Core temperatures and stability are closely related. Even with Vcore at 1.25'ish, unless your 7700K is delidded under a custom loop at low ambient temperature, most users find it difficult to achieve Core temperatures below 80°C under your conditions without AVX offset.

Nevertheless, here's a more detailed explanation of the AVX issue:

“Stress” tests vary widely and can be characterized into two categories; stability tests which are fluctuating workloads, and thermal tests which are steady workloads. Intel tests their processors at a steady 100% TDP workload to validate Thermal Specifications.

Prime95 version 26.6 Small FFT's is ideal for CPU thermal testing, because it's a steady 100% workload with steady Core temperatures that typically runs Core i variants with Hyperthreading and Core 2 processors within +/- a few % of TDP. No other utility so closely replicates Intel's test conditions.

Utilities that don't overload or underload your processor will give you a valid thermal baseline. Here’s a comparison of utilities grouped as thermal and stability tests according to % of TDP, averaged across six processor Generations at stock settings rounded to the nearest 5%:

All tests will show 100% CPU Utilization in Windows Task Manager, which indicates processor resource activity, not % TDP workload. Core temperatures correspond directly to workload which drives Power dissipation (Watts).

As you can see on the scale above, Prime95 versions later than 26.6 are absolutely brutal due to AVX/2. Prime95 v26.6 Small FFT’s provides a true and steady 100% workload, so if Core temperatures are below 85°C, then your processor should run the most demanding real-world workloads without overheating.

4th through 9th Generation i9, i7, i5 and i3 CPU’s have AVX2 Instruction Sets. Prime95 versions later than 26.6 run AVX/2 code on the CPU's Floating Point Unit (FPU), which is an unrealistic workload that can result in Core temperatures up to 20°C higher.

Here's the nominal operating range for Core temperature:

Core temperatures above 85°C are not recommended.

Core temperatures below 80°C are ideal.

Many 6th through 9th Generation motherboards address the AVX problem by providing “offset” adjustments (downclock) in BIOS. -3 (300 MHz) or more may be needed to limit Core temperatures to 85°C. If you don’t use AVX apps, BIOS should still be configured for it, as certain utilities use AVX for stability testing.

AVX can be disabled in Prime95 versions later than 26.6 by inserting "CpuSupportsAVX=0" into the "local.txt" file in Prime95's folder. However, since Core temperatures will be the same as 26.6, it's easier to just use 26.6. As per Intel’s Datasheets, TDP and Thermal Specifications are validated “without AVX”.

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

CT

 

[The Original Ralph]

i had my 9900k at 4.9 running stable on P95 vs26.6 small FFTs, and when i'd run it with the blend test (avx) it was fine with an avx offset of 2 which brought my clock down to 4.7 when it encountered avx loads

the odd part, it would crash if i didn't set avx offset to 2, but when i ran the computer without the GPU (GTX 1070) it would handle avx loads at 4.9 clock and no avx offset. I was told the load of the GPU communicating with the CPU was greater than the load of the CPU processing the graphics itself

 

[p00kie]

... 7700K ...5ghz on 1.256v.(voltage was set to 1.235 with adaptive mod) ... passes every single stress test ... EXCEPT prime95 ... Temps are fine (around 55 max 62) ... avx offset ... makes it stable on prime95 ...

p00kie,

What is your ambient temperature?

Although you said "Temps are fine (around 55 max 62)", I take that to mean Prime95 (AVX) version 29.4 Small FFT's with AVX offset at 3. Core temperatures and stability are closely related. Even with Vcore at 1.25'ish, unless your 7700K is delidded under a custom loop at low ambient temperature, most users find it difficult to achieve Core temperatures below 80°C under your conditions without AVX offset.

Nevertheless, here's a more detailed explanation of the AVX issue:

“Stress” tests vary widely and can be characterized into two categories; stability tests which are fluctuating workloads, and thermal tests which are steady workloads. Intel tests their processors at a steady 100% TDP workload to validate Thermal Specifications.

Prime95 version 26.6 Small FFT's is ideal for CPU thermal testing, because it's a steady 100% workload with steady Core temperatures that typically runs Core i variants with Hyperthreading and Core 2 processors within +/- a few % of TDP. No other utility so closely replicates Intel's test conditions.

Utilities that don't overload or underload your processor will give you a valid thermal baseline. Here’s a comparison of utilities grouped as thermal and stability tests according to % of TDP, averaged across six processor Generations at stock settings rounded to the nearest 5%:

All tests will show 100% CPU Utilization in Windows Task Manager, which indicates processor resource activity, not % TDP workload. Core temperatures correspond directly to workload which drives Power dissipation (Watts).

As you can see on the scale above, Prime95 versions later than 26.6 are absolutely brutal due to AVX/2. Prime95 v26.6 Small FFT’s provides a true and steady 100% workload, so if Core temperatures are below 85°C, then your processor should run the most demanding real-world workloads without overheating.

4th through 9th Generation i9, i7, i5 and i3 CPU’s have AVX2 Instruction Sets. Prime95 versions later than 26.6 run AVX/2 code on the CPU's Floating Point Unit (FPU), which is an unrealistic workload that can result in Core temperatures up to 20°C higher.

Here's the nominal operating range for Core temperature:

Core temperatures above 85°C are not recommended.

Core temperatures below 80°C are ideal.

Many 6th through 9th Generation motherboards address the AVX problem by providing “offset” adjustments (downclock) in BIOS. -3 (300 MHz) or more may be needed to limit Core temperatures to 85°C. If you don’t use AVX apps, BIOS should still be configured for it, as certain utilities use AVX for stability testing.

AVX can be disabled in Prime95 versions later than 26.6 by inserting "CpuSupportsAVX=0" into the "local.txt" file in Prime95's folder. However, since Core temperatures will be the same as 26.6, it's easier to just use 26.6. As per Intel’s Datasheets, TDP and Thermal Specifications are validated “without AVX”.

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

CT

Hey,sorry for this REALLY late replay,yes my cpu is delidded and room temp is around 25c,im running some really bad cpu air cooler (Arctic freezer 13).now i have downloaded and tested with the prime95 version you had linked me with.PC passes that test at 5ghz (after 12h of testing) temps around around 50c (give or take 3c)...I have not encounter any crashes yet,and i believe that its going to be okay,thank you on your time sir!

 

[p00kie]

i had my 9900k at 4.9 running stable on P95 vs26.6 small FFTs, and when i'd run it with the blend test (avx) it was fine with an avx offset of 2 which brought my clock down to 4.7 when it encountered avx loads

the odd part, it would crash if i didn't set avx offset to 2, but when i ran the computer without the GPU (GTX 1070) it would handle avx loads at 4.9 clock and no avx offset. I was told the load of the GPU communicating with the CPU was greater than the load of the CPU processing the graphics itself

:3 i have encountered the same issue with my gtx 980 but didn`t bother listing it here,i was kinda scared that something was wrong with PSU or Motherboard until i run across thread explaining the same thing.Thanks for confirming