how to undervolt AMD X4 (640) on M3N78-em?

[li21]

hi all

just want to undervolt my cpu to reduce power, noise and heat.

my motherboard has no way of reducing voltage so i thought id try software like crystalcpuid and rmclock

now it seems the features i need to get into on those apps are greyed out of not showing...

is it possible theres no way to do it on my mobo?

what about underclocking.. if i reduce fsb in my bios.. will that reduce power usage?

right now theres noticable hum vs my last cpu which was a 5050e... not good for a htpc...

[Ethan W]

On my Gigabyte board voltage is in the Overclocking section of the BIOS, although I couldn't say where in the ASUS, but I'd be very surprised if it wasn't there somewhere...

Dropping the speed isn't really going to make enough difference to be worth it. You really want to be changing the voltage. Is there an OC utility for your board that allows you to change voltage?

[li21]

well theres nvidia nTune...

but again all the options there are greyed out too..
must be this bloody mb

[li21]

CPU-z shows the volatges are: (with Cool n quiet)


@800hmz - 1.216v
Q: I've read that this should be as low as 1.08v (without undervolting)?
How do I get this lower like it should be even without undervolting?


@3000mhz -1.232v -
Q: Isn't this lower than what the stock voltage should be ?

[Jon187]

Goodluck with the search mate and best of luck with the little one (your daughter, not the CPU).

[Ethan W]

Originally Posted by li21

@3000mhz -1.232v -
Q: Isn't this lower than what the stock voltage should be ?

Looks like it.

From some review screenshots, the stock voltage is about 1.3V. That said, it all depends on the chip. If you happen to have a great CPU, the stock voltage is going to be lower. If it's stable, I wouldn't worry too much.

Have you had a chance to dig further into the BIOS? Also, give AMD Overdrive a look.

[li21]

Thanks Jon! and you too,
bTW the CPU flies through my trancoding now

@Ethan.. As I was telling Jon the other day, my mobo is an Nvidia chipset so over drive doesn't work. Needs to be amd chipset
Definitely no options to under volt in the bios.

[Asteroid]

It will definitely be there. If it's like my old K8V-X, you'll need to disable Cool and Quiet to do it (which may not be practical).

[Ethan W]

Originally Posted by Asteroid

It will definitely be there. If it's like my old K8V-X, you'll need to disable Cool and Quiet to do it (which may not be practical).

Oh, that just made me think: would PhenomMsrTweaker work? AFAIK, it lets you adjust each of the P-States, voltage and all, from within the OS.

http://phenommsrtweake.sourceforge.net/

[li21]

Originally Posted by Ethan W

Oh, that just made me think: would PhenomMsrTweaker work? AFAIK, it lets you adjust each of the P-States, voltage and all, from within the OS.

http://phenommsrtweake.sourceforge.net/

Thanks, will check itmut and post results!

[li21]

Ethan... That WORKED! Thanks!!

I managed to customize CPU vid and NB vid from that app..

Have you used this yourself?
My question in why would we use the custom cool n quiet when the regular cnq will just work with the new vids from with in each p-state we tweaked?

Or is custom cnq more about when it switches states?

If my CPU stock volatge is 1.3 and mine only draws 1.23v at load... How much more can I push it down?( rhetorical question,..Doing a prime95 stress test now @1.20v)

[Ethan W]

Originally Posted by li21

Ethan... That WORKED! Thanks!!

I managed to customize CPU vid and NB vid from that app..

Have you used this yourself?
My question in why would we use the custom cool n quiet when the regular cnq will just work with the new vids from with in each p-state we tweaked?

Or is custom cnq more about when it switches states?

If my CPU stock volatge is 1.3 and mine only draws 1.23v at load... How much more can I push it down?( rhetorical question,..Doing a prime95 stress test now @1.20v)

Good to hear. I haven't actually used it myself, because I generally don't use CnQ. I lock the clock and and voltage at my desired setting. But I've seen others use it in the past.

I'm guessing the custom CnQ is, as you suggested, to define when the steps kick in. If you want to save more power, you might want it scaling down more aggressively (soon), or you might want the possible performance boost that comes from leaving it longer before scaling down after a load finishes (for example, in a constantly spiking-dropping load, the time taken to realise the load has increased and to speed up might slow things down). All speculative, though; I haven't actually used the application myself.

If you have the time, you should be able to undervolt at each voltage state (especially the top and bottom states, where you're spending the majority of the time) and not just at the max clock speed. I'd be defining the lowest voltage for 3GHz and then working down the list of each state or maybe just the lowest (is that 800MHz for you?)