Vcore for i7-8700k at 5,0Ghz

[Se7enEle7en]

Hi y'all !

 

So right now my i7-8700k is OC on all cores to 4,7Ghz with Vcore set at manual on 1.19. Running smooth no problem with that but i want to OC close or at 5,0Ghz on all cores and was looking for the baseline for the Vcore at this frequency. What am looking for is a baseline where i can start from and adjust if the temps or stability has issue ! Right now with the all cores at 4,7Ghz the temps are in the mid 60's when under heavy load. The ambient temps in my room is quite good since i live in a basement with A/C during summer time so i'm not worried to push the CPU a bit further on frequency and voltages !

 

Thanks in advance y'all

[Dedayog]

Just now, Se7enEle7en said:

Hi y'all !

 

So right now my i7-8700k is OC on all cores to 4,7Ghz with Vcore set at manual on 1.19. Running smoothing no problem with that but i want to OC close or at 5,0Ghz on all cores and was looking for the baseline for the Vcore at this frequency. What am looking for is a baseline where i can start from and adjust if the temps or stability has issue ! Right now with the all cores at 4,7Ghz the temps are in the mid 60's when under heavy load. The ambient temps in my room is quite good since i live in a basement with A/C during summer time so i'm not worried to push the CPU a bit further on frequency and voltages !

 

Thanks in advance y'all

I'd start at 1.30 for 5GHz.  I am at 1.32 at 5, personally.

[Captain_Chicken]

Every CPU is different and it is impossible to give a recommended voltage for 5ghz. The way to do it would be to increase the voltage and benchmark until temps are as high as you are comfortable with. After that, increase the cpu speed 100mhz at a time until the computer is unstable.

[Se7enEle7en]

7 minutes ago, jstudrawa said:

I'd start at 1.30 for 5GHz.  I am at 1.32 at 5, personally.

Thanks will try this when i get home from work tonight ! i know every chip is different (sillicon lottery) but what are the temps under heavy load at 1,32 looks like ?

[Se7enEle7en]

6 minutes ago, Captain_Chicken said:

Every CPU is different and it is impossible to give a recommended voltage for 5ghz. The way to do it would be to increase the voltage and benchmark until temps are as high as you are comfortable with. After that, increase the cpu speed 100mhz at a time until the computer is unstable.

I'm aware of that but was curious about maybe an average Vcore for the i7-8700k ! I was suprised when i stabilize my 4,7Ghz on all cores at Vcore 1,19 and thought the Vcore was too low but never had a BSOD or stability issue so i left it on this setting for almost 1 full year now 

[Mister Woof]

Voltage doesn't go up linearly in relation to frequency

 

1.19 at 4.7 is good, but what are you using to test?

 

You might be able to get 5ghz at 1.25v, 1.35v, 1.4v, or not at all.

 

 

[Se7enEle7en]

3 minutes ago, Plutosaurus said:

Voltage doesn't go up linearly in relation to frequency

 

1.19 at 4.7 is good, but what are you using to test?

 

You might be able to get 5ghz at 1.25v, 1.35v, 1.4v, or not at all.

 

 

It's been 1 year since all the testing was done but i used CB R15, 3dMark for both GPU and CPU and stress test using OCCT and Aida64 without any crashes at 1,19Vcore.

Never tried higher then 4,7Ghz so kinda curious to see if i'll be able to get there !

 

EDIT : I use both MW Info or monitor and FPS Monitor (steam software) for in game monitoring

[Mister Woof]

Just now, Se7enEle7en said:

It's been 1 year since all the testing was done but i used CB R15, 3dMark for both GPU and CPU and stress test using OCCT and Aida64 without any crashes at 1,19Vcore.

Never tried higher then 4,7Ghz so kinda curious to see if i'll be able to get there !

Trial and error then.

 

I'd set it to 1.35v as a limit for non delidded chip, and start off at 5ghz.

 

If it's stable after your preferred testing gamut, lower voltage by 5mv and continue lowering until it's no longer stable, then go back up 5mv.

 

If it's not stable, leave it at 1.35v and go down in frequency until it is.

[Se7enEle7en]

1 minute ago, Plutosaurus said:

Trial and error then.

 

I'd set it to 1.35v as a limit for non delidded chip, and start off at 5ghz.

 

If it's stable after your preferred testing gamut, lower voltage by 5mv and continue lowering until it's no longer stable, then go back up 5mv.

 

If it's not stable, leave it at 1.35v and go down in frequency until it is.

Will do and post result tonight after work ! Thank you good sir !

[Mister Woof]

3 minutes ago, Se7enEle7en said:

Will do and post result tonight after work ! Thank you good sir !

I would avoid the most aggressive levels of LLC once you start going into the manual vcore of 1.3v+

 

But a moderate level is probably a good idea as long as you don't observe spikes above 1.4v

[Se7enEle7en]

Just now, Plutosaurus said:

I would avoid the most aggressive levels of LLC once you start going into the manual vcore of 1.3v+

 

But a moderate level is probably a good idea as long as you don't monitor spikes above 1.4v

I left LLC on default setting for my current OC ! Should i change something for 5ghz or higher Vcore ? Only thing i did was disabling the Intel C-State last year when going threw the process. 

[Mister Woof]

Just now, Se7enEle7en said:

I left LLC on default setting for my current OC ! Should i change something for 5ghz or higher Vcore ? Only thing i did was disabling the Intel C-State last year when going threw the process. 

Change power limits to maximum.

 

See how much droop you get in vcore under load; if it is a lot (more than 20mv off your target) or causes you to crash then apply a bit higher LLC. It will possibly result in vboost spikes but as long as it's not too high and your temps are ok, it will be fine.

[.Apex.]

44 minutes ago, Se7enEle7en said:

So right now my i7-8700k is OC on all cores to 4,7Ghz with Vcore set at manual on 1.19. Running smooth no problem with that but i want to OC close or at 5,0Ghz on all cores and was looking for the baseline for the Vcore at this frequency. What am looking for is a baseline where i can start from and adjust if the temps or stability has issue ! Right now with the all cores at 4,7Ghz the temps are in the mid 60's when under heavy load. The ambient temps in my room is quite good since i live in a basement with A/C during summer time so i'm not worried to push the CPU a bit further on frequency and voltages !

Impressive that you can get 4.7Ghz at 1.19, are you sure that's what the CPU is getting though? you should never trust the BIOS to supply voltage based on what you set, because of LLC the voltage might be way higher than what you actually set during Idle/Load

But anyway, I would start at 1.3V and always pay attention to voltages in HWinfo, you should be able to get a stable overclock between 1.3-1.35V, might be even lower if 1.3 works

[.Apex.]

And disable CPU SVID Support

[Se7enEle7en]

1 minute ago, Plutosaurus said:

Change power limits to maximum.

 

See how much droop you get in vcore under load; if it is a lot (more than 20mv off your target) or causes you to crash then apply a bit higher LLC. It will possibly result in vboost spikes but as long as it's not too high and your temps are ok, it will be fine.

Sorry for the maybe stupid question but when you say power limit to maximum you mean in the bios right ? Because everything else is done for the power in Windows

[.Apex.]

Just now, Se7enEle7en said:

Sorry for the maybe stupid question but when you say power limit to maximum you mean in the bios right ? Because everything else is done for the power in Windows

yes, BIOS

[Se7enEle7en]

2 minutes ago, _Syn_ said:

Impressive that you can get 4.7Ghz at 1.19, are you sure that's what the CPU is getting though? you should never trust the BIOS to supply voltage based on what you set, because of LLC the voltage might be way higher than what you actually set during Idle/Load

But anyway, I would start at 1.3V and always pay attention to voltages in HWinfo, you should be able to get a stable overclock between 1.3-1.35V, might be even lower if 1.3 works

The max reading i get for Vcore in MW Info is 1,216 when the Vcore is set to manual at 1,19 in the bios ! 

[Se7enEle7en]

Just now, _Syn_ said:

yes, BIOS

alright it's done already i believe when i OC at 47 my buddy who has way more XP then me on overclocking show me the basic and i believe we did set the power to maximum but i'll double check tonight

[Se7enEle7en]

1 minute ago, Se7enEle7en said:

alright it's done already i believe when i OC at 47 my buddy who has way more XP then me on overclocking show me the basic and i believe we did set the power to maximum but i'll double check tonight

Where is the option for the power limits on a Asus Prime z370-A mobo just to be sure and avoid me going into research mode for this lol

[.Apex.]

Just now, Se7enEle7en said:

The max reading i get for Vcore in MW Info is 1,216 when the Vcore is set to manual at 1,19 in the bios ! 

Oh that's great then, your CPU seems to be above average

 

[Se7enEle7en]

Just now, _Syn_ said:

Oh that's great then, your CPU seems to be above average

 

Thanks after a lot of research of OC i had the same conclusion but since i had no other experience with Coffee Lake was not sure if this was average or above average just thought the Vcore was low for 6c/12t at 1,19

[.Apex.]

Just now, Se7enEle7en said:

Where is the option for the power limits on a Asus Prime z370-A mobo just to be sure and avoid me going into research mode for this lol

"Internal CPU Power Management" in "AI Tweaker"

Long duration Package Power Limit - 4095
Short Duration Package Power Limit - 4095

IA AC Load Line - 0.01
IA DC Load Line - 0.01

and in AI Tweaker, just under Tweaker's Paradise there's something called "CPU Core/Cache Current Limit Max", set that to 255.75

[Se7enEle7en]

7 minutes ago, _Syn_ said:

And disable CPU SVID Support

I know what SVID is used for but can you elaborate on why it's important to turn it off (disable) when doing OC and manuel Vcore voltage ?

[.Apex.]

Just now, Se7enEle7en said:

I know what SVID is used for but can you elaborate on why it's important to turn it off (disable) when doing OC and manuel Vcore voltage ?

so the CPU doesn't decide voltages on its own and mess everything up, from my experience (I have the same board), while having SVID enabled, I got a shit ton of voltage fluctuation, maybe it's a bug I don't know, but I disabled it since and never looked back

[.Apex.]

3 minutes ago, _Syn_ said:

so the CPU doesn't decide voltages on its own and mess everything up, from my experience (I have the same board), while having SVID enabled, I got a shit ton of voltage fluctuation, maybe it's a bug I don't know, but I disabled it since and never looked back 

Some say SVID gets ignored when you set manual voltage, but that wasn't my case, but that was a year ago, i don't know if they fixed that with BIOS updates

It shouldn't be on when you overclock anyway, whether it's a bug or not