What is the maximum AVX offset when executing 8700k downclocking?
What is the maximum AVX offset when executing 8700k downclocking?
Adjusted my 8700k processor to 4.6ghz across all cores using 1.27v and an LLC level 3. BIOS AVX offset was set to 2, but Prime95 shows clock speeds dropping to 4200mhz instead of the expected 4400mhz when offset is 2. Power limits are at maximum, Core VIDs are requesting 1.3 to 1.42v. Disabling AVX in testing returns normal AVX offset values between 4600mhz and 4400mhz. With AVX active, speeds remain consistently around 4200mhz. Am I making a mistake in the overclocking process?
Many 8700K systems aimed for a minimum of 4.7 GHz across all cores, since that was the maximum turbo setting available on a single core.
I would think about reverting your BIOS to its default configuration, activating XMP, turning on MCE (which aims for 4.7 GHz on all cores if thermal and power limits permit), then possibly setting up or adjusting Intel's XTU for AVX offsets, making voltage tweaks per core, targeting the exact desired clock speeds, etc. In case of a crash or a rough shutdown, XTU will revert to standard settings, avoiding any complications with BIOS adjustments.
When performing a multiplier sync, the frequency shouldn't change much in non-AVX Prime95 tasks. If the CPU is throttling before the AVX offset is applied, the issue might still relate to VRM temperatures. Are you checking HWInfo and monitoring package thermals and power limits? Are you setting 1.27v because it was unstable at lower voltages? x46 all-core could work on stock vcore. Consider using LLC at 4 or 5. When you reached your overclock, were you running AVX tests or just non-AVX? What's your cooling setup? What's your motherboard?
Mobo is an Asus Prime Z370-A. I encountered a BSOD while using both on Prime95. AVX was enabled and then disabled. The cooling performance is solid. Under stress testing after 10-15 minutes, the max CPU package temperature reached 75-79°C. In Hwinfo64, there are no limits or throttling applied to my CPU. The cache ratio is set at 42, which might explain why it’s being underclocked to 4200mhz.
Cache (uncore) operating at 300 to 500 MHz below clock speed is acceptable. In an ideal scenario, both core and cache ratios are matched at higher power consumption. Are you employing adaptive or offset voltage control? Have you adjusted any other voltages (VCCIO, VCCSA, etc.)? If you attempt a direct jump to 1.29 V with a standard 4-stage LLC, would it still cause significant underclocking? It would be useful to check hwinfo in sensors mode for any thermal throttling during testing. What motherboard and cooling configuration are you using?
I plan to reach up to 1.29v using an LLC of 4 and check the outcomes. My voltage is set manually, and I haven't changed any other settings. The motherboard is an Asus Prime Z370-A with three intake fans on the bottom (120mm each), four exhaust fans (120mm each), and a H100i AIO 240mm for the CPU.
When AVX is turned off in Prime95, the processor maintains a consistent speed of 4.6ghz. Activating AVX results in an underclocking to 4100mhz.
These are your temperatures during this situation. Have you tried running OCCT with certain AVX tasks to record per-core and TjMax figures while testing? It could still be related to power or secondary thermal issues due to the significant drop. I might consider dropping any AVX offset and then tweaking your motherboard's TjMax to better support AVX workloads. This approach is just one idea but could be useful if your board supports it, since many modern applications now use AVX-optimized instructions. Doing this would likely prevent frequency drops in AVX offset scenarios.
On Asus boards (including the Maximus XI Hero), you can adjust the Maximum CPU Core Temperature to effectively change TjMax. Other models work similarly.
A video from Buildzoid in 2020 explored whether to use AVX offset or not. You can watch it here: https://www.youtube.com/watch?v=fmBDFYyFAcQ.
The Overclock.net article also mentions ThrottleStop as a tool that allows setting different AVX offsets if needed.
Many 8700K systems aimed for a minimum of 4.7 GHz across all cores, since that was the maximum turbo setting available on a single core.
I would think about reverting your BIOS to its default configuration, activating XMP, turning on MCE (which aims for 4.7 GHz on all cores if thermal and power limits permit), then possibly setting up or adjusting Intel's XTU for AVX offsets, modifying core voltage settings, targeting the exact desired clock speeds, etc. In case of a crash or unstable shutdown, XTU will revert to standard settings, avoiding complications with BIOS adjustments.