i7 8700k 4,7Ghz MAX Turbo Limit
i7 8700k 4,7Ghz MAX Turbo Limit
Hi guys,
I have an intel i7 8700k installed on an ASUS Z370-E Gaming motherboard with a Cooler Master MasterLiquid 240 Pro AIO cooler. I attempted to run 4.7Ghz across all cores. I configured the VCORE to Adaptive mode at 1.2 V and set Load Line Calibration to 4. In Prime95 10 seconds, the test failed with a value of 4,6 and remained stable afterward. Checking HWiNFO shows "IA: Max Turbo Limit" enabled. No other events were recorded—no throttling due to temperature or power draw. The CPU temperature stayed below 79 degrees throughout the test. What might be causing the throttling to 4,6Ghz? I attached a screenshot from HWiNFO.
Is prime performance possible across all cores?
A 8700k with boost will operate at these speeds depending on the number of cores used.
1 core 4.7
2 core 4.6
3 core 4.5
4-5 core 4.4
6 core 4.3
If prime is only running on 2 cores, the CPU would default to 4.6 GHz during boost.
My Prime95 version is 29.4 with an AVX offset of 0. The limit on all cores was set to 47, but it dropped to 47 for the first 20-30 seconds before going to 46 afterward. All cores are now running.
nightmare392 :
My Prime95 version is 29.4 with AVX offset at 0. I've set the limit on all cores to 47, and they initially stayed at 47 for the first 20-30 seconds before dropping to 46 afterward. The performance was consistent across all cores. You mentioned setting vcore to 1.2, but your HWINFO shows 1.152. Would changing LLC to 5 help? Is there a significant drop in performance? How long did you run the program? I checked Version 26.6 as well.
My core setting is 1.2 adaptive, not fixed. I plan to adjust LLC to 5, though it could raise temperatures. I completed a prime run for roughly an hour. The same results appeared in a large FFT (512-4096).
nightmare392 :
My vcore is configured at 1.2 adaptive, not fixed. I plan to adjust LLC to 5, though it could raise the temperatures. I ran prime for roughly an hour.
Any change in core voltage will affect the temps, as you understand.
It's odd that you're losing a bin without any power or temperature issues.
That is what i can't understand. There is no reason to throttle. Temps are good, power limit is not reached, vrm is not too hot to cause throttling. Maybe it's not getting enough vcore. Should i try to increase to 1.25V and see if it can hold 4,7? It seems a bit too much 1.25V for 4.7Ghz.
nightmare392 :
That is what i can't understand. There is no reason to throttle. Temps are good, power limit is not reached, vrm is not too hot to cause throttling. Maybe it's not getting enough vcore. Should i try to increase to 1.25V and see if it can hold 4,7? It seems a bit too much 1.25V for 4.7Ghz.
I'd try upping LLC first.
Low voltage is my thinking also. Since your using Prime ver 29 which use AVX instructions, it may be dropping a bin. Normally this would just be unstable, though.
Have you set AC/DC load lines to 0.01?
How do you know that VRM is not hot? I wouldn't think that they are considering vcore, Just curious.
The AC/DC load lines are configured at 0.01. Keeping them on Auto was triggering VR Thermal Alert and throttling, likely because the motherboard was assigning an excessively high value. I plan to adjust the LLC tomorrow after returning from work. If that doesn’t resolve the issue, I’ll attempt to raise Vcore. Meanwhile, I had to adjust VCCSA to 1.3 and VCCIO to 1.25 so my G.Skill 3200Mhz memory would function with XMP enabled. I gradually increased the values from 1.1 and 1.15 until I achieved stability in Prime95 (512k-4096K). The settings appear high, but nothing under these conditions worked consistently. The DRAM voltage is set to 1.35 via XMP. I tested 1.36 with VCCIO and VCCSA at 1.15 and 1.2, but it failed in Prime95. It has been running for two hours without errors now, though I remain concerned that the 1.3V VCCSA might be slightly too high.