Phenom II voltage in BIOS doesn't match AMD OverDrive value

[ET3D]

I've been undervolting my Phenom II X6 1090T using AMD Overdrive to allow me to fold while keeping the heat and therefore fan noise down. The normal voltage OverDrive shows me is 1.35V, and I lower it to 1.25V without an issue, and the difference is quite noticeable (5 degrees C and quite a bit less noise). The problem is that every time I take my PC out of sleep (I don't fold 24/7, just when I'm doing something else on my PC) I have to run OverDrive and set the voltage again.

 

It looked to me like the obvious solution would be to change the voltage in the BIOS of my Gigabyte GA-MA790X-UD4 (AM2+ board), but the value there is 1.475V, which is unrelated to what I see in OverDrive, and changing it didn't seem to affect the 1.35V value OverDrive shows.

 

Can anyone explain what I'm seeing and help me set the voltage so that it always starts at 1.25V when the PC starts?

[Black64]

What you are seeing is that when you adjust CPU settings the setting aren't permanent, they are temporary because you are using a software OC. Which means that when you are in the BIOS Overdrive cannot control the CPU because it is not running. The BIOS has control of the CPU when ever the PC is on. Overdrive can only work when you are in the OS. That is why it's better to OC using only the BIOS.

[ET3D]

After a little discussion at the Anandtech I was referred to PhenomMsrTweaker, and running that helped me realise the different voltages related to different performance states. The BIOS controls P0 and AOD controls P1. Since PhenomMsrTweaker can control all of them, and set them on wake up, that looks like the perfect solution for my needs.

[ivangela]

After a little discussion at the Anandtech I was referred to PhenomMsrTweaker, and running that helped me realise the different voltages related to different performance states. The BIOS controls P0 and AOD controls P1. Since PhenomMsrTweaker can control all of them, and set them on wake up, that looks like the perfect solution for my needs.

 

What is PO and P1. Excuse my ignorance.

[ET3D]

What is PO and P1. Excuse my ignorance.

 

Here's an explanation.

 

The Phenom II X6 1090T has 5 states, P0 (highest performance) to P4 (lowest). P0 is what is used when it runs at maximum performance (turbo core), and P1 is the normal maximum speed, which is what the cores run when all are in use.

[ivangela]

Here's an explanation.

 

The Phenom II X6 1090T has 5 states, P0 (highest performance) to P4 (lowest). P0 is what is used when it runs at maximum performance (turbo core), and P1 is the normal maximum speed, which is what the cores run when all are in use.

 

Interesting, thanks. So voltage and frequency is determined by % load according to that article. That seemed to be an old article though, as determined from the CPUs and GPUs they were calling cutting edge. I wonder if load still determines voltage and frequency. The reason I ask is if I am folding using all cores can the CPU still throttle back the voltage and frequency at which I fold?

[ET3D]

Based on only my experience load does determine the state, and therefore frequency and voltage. As I mentioned the Phenom II X6 uses P1 when all cores are active. I don't think it will scale down from that or go higher to P0. So basically you have to make P1 have the voltage and frequency you want to fold with. I don't know how it works on other CPU's, though I imagine it'd be similar, with P0 and perhaps even P1 reserved for when only a few cores are active and the chip can go turbo.

 

Edit: Since your Phenom II X4 doesn't support turbo core, it's possible that P0 is what's used when all cores are active. That would make things simpler.

Edited November 5, 2011 by ET3D