[SOLVED] Need Help With i7 8700K @ 4.7GHz (ASRock Z390 Extreme4)

[stevenj31696]

Hello everyone, just wanted some opinions on this overclock. This is running Prime95 Small FFT's for about 30 min. As far as voltages go I think this is pretty good. Running a Corsair H100i for my CPU cooler and I'm kind of concerned about the temps but I know under normal usage my PC will never get this hot. At idle I'm around 30C on the package.

In BIOS:
4.7GHz Multiplier
Offset Voltage of -75 with Load Line Calibration on Level 5 (I can run 4.7GHz on a lower voltage [1.15-1.18] than the factory settings, which is 4.3GHz running @ 1.28 vCore weird??)
Everything else is set on Auto I think because I didn't adjust much

Also, would anyone know why when I run Blend test in Prime95 I get around a 1.21 vCore. Is that normal?? Temps still never exceed 91C on package or cores.

UPDATE: Got an error running Blend in Prime95, does it need more voltage? I've got my RAM (G.SKILL RGB 3000MHz) running the XMP Profile so I don't think that could be it...

**UPDATE** : Fixed the error in Prime95 with a little more vCore and a +0.05 increase on my RAM's voltage

Any help and opinions are appreciated!

 

[stevenj31696]

Bump for help and answers plz
Yesterday I bumped my Long duration and short duration power limit to max and set long duration maintained to 1 second. Seemed to make my vcore go up to a max of 1.26 (still less than my mobo was giving my Cpu @ stock speeds), and crashed if I tried to run less vcore but I got 2c lower temps.

Now I'm getting a rounding error again in Prime95 when running 8K, 4096K, Run FFTs in place, 15 min but I did return my memory to stock voltage because in my Bios I'm using xmp profile which is 1.35v, but in the Bios HW Monitor they are receiving 1. 365v so I don't think that is the reason I'm getting errors in prime. Going to run memtest tonight and find out for sure unless anyone else has an idea, I'm not trying to run more voltage on my Cpu as I really don't want it to much past 90C at all when stress testing. Trying to make this Cpu last

Also does this mean I need to install my RAM into A2 and B2?? Cuz if so I'm dumb

 

[vMax]

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...

 

[vMax]

Also RAM for dual channel mode on your motherboard should slot into A2 and B2...

 

[stevenj31696]

@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.