Disabling core on AMD Phenom II?

[GoogalyMoogaly]

Hi,

So I've decided to put my mATX AM3 motherboard and Phenom II X6 1055T into my 'HTPC'.
You're all probably thinking like me, why do you need 6 cores in an HTPC?
As you've probably guessed from the title, I don't.
Now disabling the cores is easy on my motherboard (Gigabyte GA-880GM-UD2H). What it doesn't seem to do is lower the VCore at all.

Am I just wrong in expecting a 4 core PII to use less VCore than a 6 core PII?
Is that not how it works?

So I guess I'll need to do it manually?
The 1055T is 2.8GHz with a 3.3GHz boost. Knocking this down to 4 core makes it close to a PII X4 925 I believe. What sort of VCore would you expect from that?

Does it seem reasonable to expect to be able to lower my VCore to that sort of range?

 

[TheMorningStar]

I thought vcore was pretty much the same @1.35vcore for all, maybe not some LP versions I seem to half remember.

You could try downclocking or voltage tweaking within windows, if using windows. AMD Overdrive for example. Personally I'd leave all 6 cores and just use Cool & Quiet with windows Power Schemes. You can set the ghz in advanced settings also If you didn't want a dynamic clock rate and just wanted 800mhz or any of the other Cool & Quiet steppings.

 

[eddiew]

There's no real reason that the required vCore would be less for a 4-core than a hex - the same voltage is fed independently to each core, not divided between them.

I would actually expect you to get more of a vCore reduction by keeping all 6 active, and lowering the frequency.

Maximum power/heat will come down with lowering the core count, however, since power use is proportional to voltage, frequency, and number of transistors in use. Reducing any of these will reduce the power at '100%' load.

 

[pandem0nium]

I'd turn off boost. It uses a lot of power and the volts it applies is more than you would need to overclock it manually.

Incrementally lower the voltage until it becomes unstable, stress testing with Prime95.

 

[Scougar]

Why do you want to disable the cores? It will not use the cores unless it needs them.

 

[GoogalyMoogaly]

Why do you want to disable the cores? It will not use the cores unless it needs them.

Yeah, I did think that too.

Fair enough, might just leave it then. Well until I can be bothered to just manually undervolt it. I seem to remember the chip being really good on voltage up to 3.5GHz, so at stock it'll hopefully come down a bit from stock.