My 1800x/2700x clock/voltage scaling

Soulkeeper

Diamond Member
Nov 23, 2001
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#1


I spent some time making this chart. To test for stability I compiled firefox source while watching youtube.
As I was doing all this the reported cpu temps were pretty low topping out at 60c.
The odd thing is that after all these were confirmed stable, the next day when ambient was about 10F higher, voltages needed were atleast 0.05v higher for the clocks I tested.

What have you guys noticed for 4GHz voltages needed ?
Have you noticed more voltage being needed as temps go up ?
 
Last edited:

amd6502

Senior member
Apr 21, 2017
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#2
Yes, that makes a lot of sense. Higher temps means more "noise" for the silicon; so something is needed to overcome that, either going back on frequency a little, or higher voltage, which I wouldn't recommend here because it's already too high.
 

Soulkeeper

Diamond Member
Nov 23, 2001
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#3
yeah, short of water cooling I think the best I can manage 24/7 is 3.8GHz ~1.3v
 
Apr 27, 2000
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#4
To reach 4.0 GHz in nearly every test/benchmark on my 1800x, I have to use 1.375v + level 3 LLC. It chews up a lot of power. Backing off a few MHz makes things a lot more efficient. But I didn't set up this machine to be exclusively efficient.
 

Soulkeeper

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Nov 23, 2001
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#5


I purchased a 2700x 50th and made a comparison for anyone that is interested.
Of course the 50th edition is identical to a regular 2700x.
Hopefully someone will find this interesting, took me hours to stability test each setting.

gamersnexus of course beat me to the punch with his results, which seem similar to the ones I got.
No real surprises here.
 
Apr 27, 2000
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#6
Pretty good voltage curve for the 2700x. What is your power consumption like at 4.2 GHz?
 

Soulkeeper

Diamond Member
Nov 23, 2001
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#7
Pretty good voltage curve for the 2700x. What is your power consumption like at 4.2 GHz?
Just running a quick synthetic test it looks like around 215watts on my kill-a-watt
 

Markfw

CPU Moderator, VC&G Moderator, Elite Member
Super Moderator
May 16, 2002
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#8

Soulkeeper

Diamond Member
Nov 23, 2001
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#9
Yes, the whole system without stressing the graphics or hd's of course.

Right now i'm having problems with buggy custom pstate settings in this motherboard.
It likes to stay at pstate0 and ignore the others. ohh well
So it's idling around 88Watts at 4.1GHz


I wanted to set these pstates in the bios for my 24/7 use, but it refuses to work.
Enabled - FID = A4 - DID = 8 - VID = 2D - Ratio = 41.00 - vCore = 1.26875
Enabled - FID = 98 - DID = 8 - VID = 4D - Ratio = 38.00 - vCore = 1.06875
Enabled - FID = 78 - DID = 8 - VID = 7A - Ratio = 30.00 - vCore = 0.78750

Also i've experimented with the vSOC and it runs stable down to 0.8375v with my mem at 3000MHz
The 1800x needed about 1.05v
 
Last edited:
Sep 4, 2016
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#11
P-States might work if you set only the lowest and the highest ones... Try to not change the ones in the middle of the curve
 

Soulkeeper

Diamond Member
Nov 23, 2001
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#12
This bios is flaky, worked once or twice changing only the fid in pstate0 ... out of well over a dozen reboots and cmos clears.
It required a cmos clear most everytime it didn't like a setting.

I downgraded to the january bios version and it appears to be working now.
 

Soulkeeper

Diamond Member
Nov 23, 2001
6,418
19
91
#13
I just managed to get my 4x16 hynix running at 3133MHz
it takes 1.38v 16-18-16-18-37 timings
I kept corrupting the bios trying to get 3200MHz stable, looks like it would need ~1.44v and possibly better cooling
 

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