• Welcome to Overclockers Forums! Join us to reply in threads, receive reduced ads, and to customize your site experience!

i7 8700K gone wrong

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.
OP
M

Meenfil

Registered
Joined
Nov 9, 2018
Location
Sherbrooke
Sometimes improving cooling significantly can allow you to lower the core voltage a tad at a given level of overclock but not lower it as much as you experienced. Undoubtedly, there is another factor at work here to allow you to get by with so much less core voltage. Did you make other changes in bios and have you done sufficient stress testing to confirm it is in fact stable?

Both tests were run at stock clock, since the purpose was to restart from the beginning after unsuccessful OC attempts. I did remember yesterday that i did update my BIOS recently. My cooling improvement and the BIOS update are the only variables that have changed.
 

Johan45

Benching Team Leader Super Moderator
Joined
Dec 19, 2012
Both tests were run at stock clock, since the purpose was to restart from the beginning after unsuccessful OC attempts. I did remember yesterday that i did update my BIOS recently. My cooling improvement and the BIOS update are the only variables that have changed.

Looks much better Meenfil and that's normal for P95 as it cycles through the different FFT lengths, some are just a lot harder on the CPU. As for the lower voltage that could easily be from a BIOS update
 
OP
M

Meenfil

Registered
Joined
Nov 9, 2018
Location
Sherbrooke
Looks much better Meenfil and that's normal for P95 as it cycles through the different FFT lengths, some are just a lot harder on the CPU. As for the lower voltage that could easily be from a BIOS update

Good, so much lower temps due to the cooling upgrade and lower voltage due to the Bios Update. So what would you suggest as the next steps since you mentionned that i was starting in the middle and not at the beginning?

My target is to be stable at 5Ghz if i'm not too high on voltage (to see a real difference in perfs), otherwise 4.9, or 4.8 etc.

Thanks
 
Last edited:

Johan45

Benching Team Leader Super Moderator
Joined
Dec 19, 2012
I would start by setting a manual voltage in BIOS of 1.25 V. Then up the multi and test. You could likely start around 4.7 GHz with testing. If it fails you need more juice, if it passes then test 4.8 and so on. Keep an eye on your temps and give the p95 test at least 20 minutes that's when it hits some of the hotter tests. From my experiences, the 8700K without delidding starts to have heat problems in the 1.3-1.35V range and P95 depending on TIM quality. Most likely at that point you could set 5.0 with a -2 AVX offset and be fine but you may get a bit more depending on you CPU.
 
OP
M

Meenfil

Registered
Joined
Nov 9, 2018
Location
Sherbrooke
Results of my testing tonight.

Clock = 4.8Ghz
Icue put on Extreme mode
Tests done on Prime P95
Voltage sensors (aida extreme & CPUZ)
Temperature sensors (HWinfo64 & Aida extreme)
LLC = 4. I did try 3 and it was overvolting. Let me know if you think voltages below are okay or if i should play more with LLC

Test #1 : 1.29v set - 1.288v actual under loading - failed after 5 minutes
Test #2 : 1.30v set - 1.304v actual - failed after 5 minutes
Test #3 : 1.31v set - 1.312v actual - failed after 15 minutes
Test #4 : 1.32v set - 1.32v actual - failed after 24 minutes - max temps - 83-90 depending on the cores
Test #5 : 1.325v set - 1.328v actual - failed after 32 minutes - max temps 84-90 depending on the cores
Test #6 : 1.33v set - 1.336v actual - didn't fail after 1 hour - stopped it manually - max temps 84-91 depending on the cores


I am fairly disappointed to be that high in voltage, and don't think it will be really safe for that chip to be clocked to 4.9 or 5Ghz if i want to keep it for a few years.

Now my questions would be :
- Is everything i did there right? or should i adjust a few things?
- Should i test it more than 1 hour to be sure before running it like this for gaming?


Thanks for the support !!
 

Johan45

Benching Team Leader Super Moderator
Joined
Dec 19, 2012
Your CPU will be fine, especially if it's not going to see heavy loads. I would go to BIOS and set a -2 offset for AVX then set the multiplier to 50 and just use it. See how things go with gaming etc..
 
OP
M

Meenfil

Registered
Joined
Nov 9, 2018
Location
Sherbrooke
Your CPU will be fine, especially if it's not going to see heavy loads. I would go to BIOS and set a -2 offset for AVX then set the multiplier to 50 and just use it. See how things go with gaming etc..

Do you mean without giving it more voltage? If i'm stable 4.8ghz 1.336v now, won't i lack voltage if i go 5ghz with 2 avx offset? I understand some applications like Prime95 will keep it at 4.8 but what about when it will run at 5ghz?
 

EarthDog

Gulper Nozzle Co-Owner
Joined
Dec 15, 2008
Location
Buckeyes!
It's the avx instructions which use more power and need more voltage. Try it and see. You may need a little bump...the only way to know is to try. ;)
 
OP
M

Meenfil

Registered
Joined
Nov 9, 2018
Location
Sherbrooke
It's the avx instructions which use more power and need more voltage. Try it and see. You may need a little bump...the only way to know is to try. ;)

Right, it was the time for me to go and learn on it :) So basically if i understand well for very demanding applications with this setup, my CPU will remain at 4.8ghz, while boosting to 5Ghz for games and non avx workloads.

I'll try that out today with current voltage and see.

Thanks guys !
 

Kenrou

Member
Joined
Aug 14, 2014
If you have the multi at x50 wouldn't it make more sense to say that it's at 5ghz normally but then lowers to 4.8ghz when it detects AVX ?
 
OP
M

Meenfil

Registered
Joined
Nov 9, 2018
Location
Sherbrooke
Okay so earlier this week i had to re-install windows for something unrelated and after re-setting everything as it was before i had to crank the voltage up to 1.335 (versus 1.33 before) to achieve the Prime 95 stable for 1 hour (5Ghz -2 offset). I went up to 94 degrees during testing but in gaming im in the 40-50 (sometimes 60 but rarely).

The actual voltage is either 1.336 or 1.344 with LLC4. Anything i should optimize there? Go 1.34 with LLC 5? or it is not a big deal?

I had one windows crash at the beginning (BSOD error code SiUSBXp.sys). I went into the BIOS and saw that Turbo and EIST were enabled so i disabled them... since then i have been gaming for 6 hours straight without any issue.

However i am surprised when gaming the frequency is always fluctuating 4800 and 5000 hz. Is it supposed to? Is it because of the offset?

Thanks !
 
Last edited:
OP
M

Meenfil

Registered
Joined
Nov 9, 2018
Location
Sherbrooke
Guys,

so related to my frequency fluctuations, here are a few pictures from my BIOS. Do you see any reasons why my OC is not locked at 5 GHZ? Thanks !!

Image.jpg

Image-2.jpg

Image-4.jpg
 

Attachments

  • unnamed(1).jpg
    unnamed(1).jpg
    48.8 KB · Views: 140
  • unnamed2(1).jpg
    unnamed2(1).jpg
    42.4 KB · Views: 140

EarthDog

Gulper Nozzle Co-Owner
Joined
Dec 15, 2008
Location
Buckeyes!
The offset appears to be why it is fluctuating. You are set at 5 GHz with a -2 offset = 4.8 GHz.
 
OP
M

Meenfil

Registered
Joined
Nov 9, 2018
Location
Sherbrooke
The offset appears to be why it is fluctuating. You are set at 5 GHz with a -2 offset = 4.8 GHz.

Okay i thought that while gaming it shouldn’t flucutate like this... i guess all games are running some avx instructions!!?

Oh well, i’ll just keep it like this, thanks a lot everyone for the help!!