Looking for assistance with an i7 8700K running at 4.7GHz on an ASRock Z390 Extreme4?
Looking for assistance with an i7 8700K running at 4.7GHz on an ASRock Z390 Extreme4?
Hello everyone, here are some thoughts on this overclock. The Prime95 Small FFT has been running for about 30 minutes. From a voltage perspective, it seems to be performing well. I'm using a Corsair H100i cooler for my CPU cooler, but I'm a bit worried about temperatures. Under normal use, I expect my PC won't get too hot—around 30°C at idle on the package.
In BIOS settings:
- Multiplier set to 4.7GHz
- Offset voltage of -75 with Load Line Calibration at Level 5
- I can run 4.7GHz at a lower voltage (1.15-1.18) than the factory spec, which is 4.3GHz at 1.28vCore—does that seem unusual?
- Most other settings are left on Auto since I didn’t make many changes.
Also, regarding the Blend test in Prime95, I’m seeing around 1.21 vCore. Is that typical? Temperatures have never gone above 91°C on the package or cores.
UPDATE: Fixed an error in Prime95 by adjusting vCore slightly and increasing RAM voltage by 0.05. Any advice or feedback would be greatly appreciated!
You are about right with the overclock and still have plenty to play with. I have a 8700K at 4.9GHz and 1.278v on an offset overclock on a Gigabyte Z370 Gaming 7. Also DDR4 3000 in 4 x 8GB modules of the Corsair Vengeance Pro. With Prime95 version 26.6 (the one to use on Intel CPU's) blend, the load is not high thus the drop and with Small FFT's it's very high and the 8700K can hit the 80's and even 90's in some cases dependant on cooling.
Voltage and LLC is key for stability and I had to go through many rounds of Prime95 tests (for hours) before I found a stable 1.278v and high LLC for my 4.9GHz overclock....5GHz required 1.327v (others have manged 5GHz at 1.3v aarrghhhh but not mine) which I did not want for 24/7 use.
Sadly I have...
I need some assistance and clear answers. Yesterday I increased my long duration and short duration power limits to their maximums and set the long duration maintained to 1 second. It looked like this raised my vcore up to a peak of 1.26, which is still below what my motherboard was giving my CPU at stock speeds. Also, it caused a crash when I tried to run less vcore, but I got lower temperatures. Now I’m experiencing a rounding error in Prime95 while running 8K, 4096K, and doing Run FFTs for 15 minutes. I returned my memory to its original voltage because in my BIOS the XMP profile is set to 1.35V, but the hardware monitor shows 1.365V. In my BIOS HW Monitor they’re getting 1.365V, not 1.35V. I don’t think this is the cause of the errors in Prime95. I’m planning to run memtest tonight to confirm unless someone else has a better idea. I’m not trying to push the CPU beyond 90°C during stress tests—I just want it to last. Also, does this mean I should install my RAM in A2 and B2? Because if so, that would be a mistake.
You are about right with the overclock and still have plenty to play with. I have a 8700K at 4.9GHz and 1.278v on an offset overclock on a Gigabyte Z370 Gaming 7. Also DDR4 3000 in 4 x 8GB modules of the Corsair Vengeance Pro. With Prime95 version 26.6 (the one to use on Intel CPU's) blend, the load is not high thus the drop and with Small FFT's it's very high and the 8700K can hit the 80's and even 90's in some cases dependant on cooling.
Voltage and LLC is key for stability and I had to go through many rounds of Prime95 tests (for hours) before I found a stable 1.278v and high LLC for my 4.9GHz overclock....5GHz required 1.327v (others have manged 5GHz at 1.3v aarrghhhh but not mine) which I did not want for 24/7 use.
Sadly I have never used a ASRock board so cannot go deep into that but I finally took the plunge and delidded my 8700K. I dropped 18 degrees C in temps immediately and now run Prime95 in the 50's and 60's...
You should be able to aim for a 4.9/5GHz at around 1.3 or less but keeping cool when testing with small FFT's is going to be key. I run a H150i Pro AIO so it has been no issues at all and with the delid, now never an issue...
Also, ensure your RAM supports dual-channel operation by fitting it into slots A2 and B2...
@vMax
Thanks for your input! Personally I don't see a need to delid because I hopefully won't need an overclock of anything more than maybe 4.8-4.9 for my purposes. I mostly game and stream with some video editing thrown in there as well.
I tried LLC Level 1 when I was messing with my settings but that made my temps go through the roof with the same vcore I was already using. Went straight to 95C instantly so I went back to LLC Level 5 and that seems to be working great so far and keeping temps in check (LLC level 5 is what I also used on my i5 2500K setup @ 4.5GHz with basically stock vcore, still running to this day with no problems what so ever).
Also I'm running the latest version of prime95 which is 29.something lol and it uses AVX correct? Which isn't really used in most applications from what I've read. However I do video editing and I know some applications can utilize AVX. I mainly use Sony Vegas tho, do you know if it utilizes it? Because if not I'll just run prime95 26.6 as I have that version of Prime as well.
Thanks for the info on the ram slots! I've got them in A1 and B1 and I even read the manual when I installed everything lol, will fix that as soon as I'm home and make a post if that fixed my rounding error in Prime.