Overclock with avx.
Overclock with avx.
My I7 7700K can run at 5ghz on 1.256v with adaptive mod. It successfully passed all stress tests including realbench, cinebench r15 20 runs, intel burn test, ada64, and even rendering a video that took about 30 minutes. Except for prime95, which sometimes shows errors unless it's running in instant mode after a short delay. Temperatures stay around 55 to 62 max. I found a fix using an avx offset that stabilizes the CPU on prime95. It's unclear if this is safe or if I should increase the voltage.
p00kie :
... 7700K ...5ghz on 1.256v (voltage adjusted to 1.235 with adaptive mod) ... all tests passed except Prime95 ... temperatures are within range (about 55 max 62) ... AVX offset contributes to stability on Prime95 ...
p00kie
,
What is your room temperature?
You mentioned "Temps are fine (around 55 max 62)", which I interpret as Prime95 (AVX) version 29.4 Small FFTs with AVX offset at 3. Core temps and stability are closely connected. Even with a Vcore around 1.25, unless your 7700K is overheating under a special loop at low ambient temperature, most users struggle to keep core temps below 80°C under these settings without AVX offset.
Still here for more details...
Do you actually run any AVX tasks? Some Adobe tools, compression, codecs, etc.? If yes, you should know whether you're aiming to increase the higher clock speeds for AVX. If you're okay with 4.7Ghz, the offset works well. Likewise, if you don't need it... then using 4.7Ghz isn't crucial, and sticking to lower voltage would be wiser than chasing AVX speeds you won't use.
Do you actually rely on the system for any AVX tasks? Some Adobe tools, compression, codecs, etc.? If you do, you should know whether you're aiming to increase AVX clock speeds. If you're comfortable at 4.7Ghz, the offset is acceptable. Likewise, if you don't use it... then the 4.7Ghz setting isn't crucial, and sticking to lower voltage would be better than forcing AVX performance you won't need. I don’t use my PC for AVX jobs. My goal is maintaining consistent in-game FPS, so I can sometimes encode videos recorded with NVIDIA ShadowPlay—though speed isn’t my main concern. What matters more is avoiding crashes from other software.
volkgren :
We typically run tests with Prime95 v26.6 to prevent using AVX. However, the AVX offset is beneficial if required. It’s the only factor causing my PC to crash (error messages appearing). Are there any other issues besides AVX-related codes that could severely stress the system? Or am I truly “crash-free” if I keep overclocking at 5.0GHz with AVX enabled on 3? Since I mainly use the PC for gaming and occasionally encode videos recorded with NVIDIA Shadowplay.
Here is the rewritten version of your text: The system operates at 7700K with a clock speed of 5ghz, running at 1.256v. The device successfully passed all stress tests except for Prime95. Temperatures remained within acceptable limits (around 55 to 62 max). The AVX offset contributed to stability during Prime95 testing. Your current ambient temperature is what you’re comfortable with? Although you mentioned “Temps are fine (around 55 max 62)”, I interpret this as referring to Prime95 performance under low temperatures. Core temperatures stayed stable, and the issue was resolved with the AVX offset. Please note the following: - Core temps are in line with expectations. - Even at a slightly higher core temperature of around 80°C, stability was maintained thanks to the AVX adjustment. - The test environment closely mimics Intel’s specifications, making it reliable for thermal evaluation. For more details on the AVX aspect, you can refer to the following resources: “Stress” tests are broadly divided into two types: stability tests with changing workloads and thermal tests with constant loads. Intel evaluates processors under a consistent 100% TDP load to confirm thermal performance. Prime95 version 26.6 Small FFTs is well-suited for CPU thermal analysis because it provides a steady 100% workload, keeping core temperatures within acceptable ranges for most CPUs. This setup closely replicates Intel’s testing conditions, making it a reliable choice for accurate thermal benchmarking. Utilities that don’t stress or under-stress the processor will offer a trustworthy thermal baseline. A comparison of tools grouped by thermal and stability tests based on TDP percentages shows consistent results across six generations of processors, rounded to the nearest 5%. All tests indicate 100% CPU utilization in Windows Task Manager, reflecting actual resource usage rather than TDP percentage. Core temperatures directly reflect workload intensity, which determines power consumption and heat generation. As shown, Prime95 versions older than 26.6 handle AVX/2 efficiently, maintaining stable performance. If your CPU runs below 85°C, it should handle demanding real-world tasks without overheating. For 4th through 9th generation i9, i7, i5, and i3 processors, AVX2 instructions are supported. Later Prime95 versions execute AVX/2 code on the FPU, which can cause core temperatures to rise by up to 20°C. Core temperatures exceeding 85°C should be avoided. Temperatures below 80°C are ideal. Many motherboards with 6th through 9th generation chipsets offer “offset” or downclocking options in BIOS to manage this. If you avoid AVX-intensive applications, BIOS settings should still support them for stability testing. AVX can be disabled in Prime95 versions after 26.6 by modifying the local.txt file in the Prime95 directory. However, since core temperatures remain similar, sticking with version 26.6 is simpler and more effective. According to Intel’s specifications, thermal performance is confirmed “without AVX” support. You may find this helpful: Intel Temperature Guide -
i had my 9900k running stable at 4.9 with P95 versus 26.6 small FFTs. When using the blend test (avx), it worked smoothly with an avx offset of 2, lowering the clock to 4.7 during avx loads. The issue arose when the GPU wasn't present, as it would crash unless the avx offset was set to 2. I was informed that the GPU's communication load exceeded the CPU's graphics processing load.
CompuTronix: 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 - 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!
The Original Ralph shared his experience with his 9900k at 4.9 running stable on P95 versus 26.6 small FFTs. When using the blend test (avx), it worked smoothly with an avx offset of 2, lowering the clock to 4.7 during avx loads. The problem arose when the GPU wasn't present, as the system would crash unless the avx offset was set correctly. Without the GPU, the load on the CPU processing graphics was manageable at 4.9 clock without an avx offset. He noted that the GPU's communication load exceeded the CPU's processing load. He also mentioned encountering similar issues with his GTX 980 but hadn't detailed it until finding a relevant discussion. Thanks for confirming.