Large changes in VCore and temperature observed at 8700k
Large changes in VCore and temperature observed at 8700k
Hi Guys
I just got my 8700k and after trying it out for a while, I chose to push it overclock. Here are my system details:
- CPU: 8700k
- Motherboard: GB Z370 HD3
- SSD: 240GB NVMe
- Graphics: GB GTX 1080 Windforce
- GPU cooler: Cooler Master MasterLiquid Pro 280
- CPU cooler: Cooler Master MasterGel Pro
I’ve been overclocking CPUs before, but never on a GB board. My current settings are:
- Overclock: 100 x 48 = 4.8GHz
- VCore in BIOS: 1.225v
- LLC enabled for turbo
I ran Cinebench twice back-to-back, AIDA64 and Realbench, everything looked fine with temps around 50-75°C. But the fluctuations were quite noticeable—temps jumped from 35°C to 75°C in a split second and then dropped rapidly after testing ended.
Prime95 1344k also ran for an hour without issues, keeping temps between 55°C and 65°C. However, Core Temp showed a VID of 1.38-1.44v even though I set it to 1.225v in BIOS.
Small FTTs also lasted an hour with temps hitting 80-90°C, sometimes spiking up to 93°C on certain cores.
I haven’t seen any BSOD errors yet. If anyone can clarify some of these terms or help me further, it would be a big relief.
Thanks!
I would dial the LLC back and then adjust the avx offset to 4.6 (-2) to control the heat from the prime 95's avx instructions. The LLC is what makes your video so high. You'll seldom see AVX unless you do a lot of transcoding or streaming. Keep in mind, some stress tests don't reflect real conditions.
UsmanGTA:
Hi everyone,
The swings are causing issues. Right away after starting tests in these programs, temperatures rise from 35° to 75° in a split second and then drop quickly once testing ends. This has been the usual pattern for years, and it remains consistent with CoffeeLake...
Intel temp sensors are integrated into the cores and detect temperatures rapidly, often several times per second. When a core experiences load, temperatures rise quickly because the heat generated exceeds what the metal coolers can handle. This is completely normal.
1. Follow the recommended approach.
2. For gaming performance testing, run Prime95 v26.6 with a small FFT. It’s the latest version with minimal AVX usage, making it ideal for a full gaming load. Any newer version includes AVX and other instructions used in different applications. V26.6 provides a solid baseline; setting the AVX offset to -2 will lower the OC by 200MHz when AVX is active, helping keep temperatures stable during high performance.
UsmanGTA:
Hi everyone,
I recently acquired my 8700k and decided to push it overclock. Here are my system details:
- CPU: 8700k
- Motherboard: GB Z370 HD3
- Storage: 240GB NVMe SSD
- Graphics: GB GTX 1080 Windforce
- Power Supply: Super Flower Silver 650W
- Cooler: Cooler Master MasterLiquid Pro 280
- Additional Cooler: Cooler Master MasterGel Pro
I'm running this setup to see if I can improve performance. My current settings are:
CPU overclocks at 100 x 48 MHz, VCore in BIOS set to 1.225v, LLC enabled.
I ran Cinebench twice back-to-back, AIDA64 and Realbench, everything looked fine with temperatures between 50-75°C. But the fluctuations were quite noticeable—temperatures spiked from 35°C to 75°C in a split second and then dropped rapidly after testing ended.
Prime95 1344k was stable for about an hour, with temps ranging from 55°C to 65°C. However, Core Temp reported a VID of 1.38-1.44v even though I set it to 1.225v in BIOS.
Small FTTs also ran for an hour, reaching temperatures between 80-90°C, with occasional jumps to 93°C on some cores. So far, I haven’t seen any BSOD errors.
If anyone can clarify a few terms or help me improve this, it would be a big relief.
Turn off turbo boost.
Mdd1963:
Hi everyone,
The temperature swings are really bothersome. Right away after starting tests in these programs, the temperatures jump from 35° to 75° in a split second and then drop just as quickly once testing ends. This is exactly the normal behavior we've experienced for years, and it remains consistent even with CoffeeLake...
Hi,
Thanks for your reply. I believe the issue might be with my AIO. I recently ran AIDA 64 for four hours, and the temperatures were in the high 80s. But neither the tubes nor the radiator are hot; they're both at room temperature. Thanks.
coretemp reading around 1.40v seems like another configuration in your bios is adjusting your 1.225v setting. The temperatures from your cooler suggest a high vcore. 1.225v won’t reach even close to 90c with this cooler. I’m not sure how the HD3 bios is configured, but I’d look into the settings and check for any changes affecting your vcore. For reference, I reached 80c max at 1.38v bios, 1.392v coretemp/cpu/hwmonitor for 5.0ghz, but I’m also using liquid metal delid.
Has turbo enabled, likely includes adaptive voltage as well, plus +offset probably exists, meaning it detects voltage changes beyond the set point and adjusts accordingly, not just responding to a specific voltage spike but also when turbo activates (typically above around 30% load).
The core temperature reading is around 1.40v, which seems to be conflicting with another setting in your BIOS that’s raising your voltage. The cooler readings suggest a high Vcore, but 1.225v won’t reach 90°C with this setup. I’m unsure how the HD3 BIOS is configured, but I’d like to investigate further to ensure the Vcore isn’t being manipulated. For reference, I achieved 80°C max at 1.38v BIOS, 1.392v with core temp/cpu/hwmonitor for 5.0GHz, and I’m also using liquid metal delid. It appears the CPU LLC and AC/DC LCC are set to Power Saving, while CPU LLC remains at Turbo. This setup feels much better now—around 1.3v idle, dropping to 1.25v under load. At 4.9GHz with 1.25v, performance is solid, though small FFTs still impact it. Pushing the voltage to 1.275 results in Cinebench taking longer but not failing, and my AIO stays cool even after many hours.
Karadjgne:
Op has turbo enabled, likely adaptive voltage too, plus +offset probably active as well. This means it detects not just a spike in vcore but also adds more adjustments when turbo activates (generally above 30% loads). Thanks for the reply. I disabled turbo yesterday and noticed no change. Multi-Core Enhancement is also turned off.