Vcore: set it manually or leave it on "auto"?

[wgoldfarb]

I just finished my first build (specs in my sig), and it passed stability testing with no problems. I wanted to take some benchmark temp readings but I noticed that VCore seems to wander all over the place if I leave it as "auto" in the Bios. At full load it goes up to 1.29, and at idle it goes down to 1.14. The MoBo seems to adjust VCore according to the load on the CPU. I am assuming this is normal, and is the way that the MoBo keeps the CPU as cool as possible. Can this have an adverse effect or is this a good thing? Could this somehow affect performance? Should I leave this setting as is, and allow VCore to wander like that, or should I manually set it to something (1.3? Something else?)

I am at stock speeds for now (2.4), and will not overclock for a few months until I learn lots more, so overclocking is not an issue for now.

 

[Shimmishim]

Do you have EIST and C1E disabled?

C1E will cause your mult to drop to 6x and the voltage to drop very low when there is no load on the cpu.

when you put a load (i.e. benching or gaming), the voltage will increase to whatever is set and up your mult to whatever you have it set to.

be sure to disable c1e and eist and also to manually set voltage in the bios.

the p5b (as well as most asus boards) suffer from vdroop when a load is put on the cpu.

i.e. let's say you manually set bios to 1.45, in windows it migh read 1.43 and then when put a load on the cpu, the voltage will drop farther down to 1.41.

 

[wgoldfarb]

Shimmishim,

Thanks, I do not have C1E or EIST disabled. I will do that now

Right now the voltage on the CPU at full load goes up to 1.28. The closest to this in the BIOS (without going below it) is 1.2875, but given the vdroop you mention I guess I should try the next higher setting which is 1.300?

Thanks!

 

[soydios]

Originally posted by: Shimmishim
Do you have EIST and C1E disabled?

C1E will cause your mult to drop to 6x and the voltage to drop very low when there is no load on the cpu.

when you put a load (i.e. benching or gaming), the voltage will increase to whatever is set and up your mult to whatever you have it set to.

be sure to disable c1e and eist and also to manually set voltage in the bios.

the p5b (as well as most asus boards) suffer from vdroop when a load is put on the cpu.

i.e. let's say you manually set bios to 1.45, in windows it migh read 1.43 and then when put a load on the cpu, the voltage will drop farther down to 1.41.

he said it all right there

 

[Modular]

Originally posted by: wgoldfarb
The closest to this in the BIOS (without going below it) is 1.2875, but given the vdroop you mention I guess I should try the next higher setting which is 1.300?

I see no reason for doing that. If you are stable at the voltage that you are running at currently, then you will do nothing by upping the vCore voltage.

 

[wgoldfarb]

wow, thanks for all the great replies.

I did as you guys suggested and it worked. I disabled C1E and EIST, set the CPU multiplier manually to 9, and set VCore to 1.275. BIOS now reports VCore as 1.24 when Idle, I guess this is the vdroop that Shimmishim was talking about. When I had it in Auto Vcore was reported as 1.27 when under full load, so I may have to increase to 1.2875 but I will do some stress tests to see if this is necessary or not.

Thanks again!