How can I underclock/undervolt the CPU?

I've done a search on here, I found one guy who said he was able to undervolt the cpu but he didn't describe how..

I'm a pretty hardcore PC user so I'm used to being able to go into the bios and just changing the multiplier or FSB when I want to adjust my CPU's performance, or else change the vcore to help it run cooler if it's overheating, etc. Unfortunately it looks like Acer has (perhaps wisely) kept these features locked up, away from PC-newbie eyes.

Does anyone know a way of adjusting the clock/volt? I'm running XP, btw. It's the XP/1gig/120gig/3cell model.

What I'm mainly interested in is seeing how low I can set my vcore before things start crashing. The fan noise doesn't bother me much (I've got 6 on my desktop PC and the one on my other notebook is fairly loud), but I'd love to coax a little extra battery life out of this thing maybe. Helping it run cooler and quieter is just a side-effect... I'd probably also underclock it a bit. For office purposes, 1.6ghz is overkill, and for most other purposes 1.6ghz won't cut it regardless. The most I really want out of this netbook is a portable work processor/web page editor/photo editor, with some old-school game from pre-2000 if I get bored.

Also if it's possible to change these settings, is it possible to adjust the shared video memory size? I think it's currently at 3mb, which is pretty pathetic considering I've got 300+ mb to spare in all the games I've tried so far.

Thanks

 

Most of the time it will be running at 800Mhz, not 1.6Ghz due to the built in frequency scaling. You can even fix it at the lower frequency if you want with the power management options in the operating system (no idea how this is done with Windows, but I assume it's possible).

Personally I'd not bother trying to underclock the CPU by fiddling with voltage, fsb etc - the operating system will do it automatically with speedstep, I can't see it really being worthwhile vs making software changes to give an extra few minutes of battery life.

Edit: Clarified what I was saying about underclocking being a waste of time.

 

It should underclock itself to 800Mhz when idle. Shouldn't CPU-Z tell you that? If you're a "hard core" PC user as you say, you should know that all Intel processors starting from the Core 2 series have Speedstep, or the ability to underclock itself.

Anyways, didn't the person who talked about undervolting say he did it with CrystalCPUID or something like that?

 

I've tried getting control over the chipset with RMclock, setfsb and Notebook Hardware COntrol but none will read the vcore nor adjust it. Setfsb is the only program that have showed any sign of control over the fsb, but all that i've been able to do really (this far) is to accidently set the fsb at 70 or so (~850MHz full speed).

 

I refer to *real* underclocking, not speedstep. Of course I know about speedstep, and it's a good idea, but it's not what I'm really after. What I'd like is the ability to underclock to maybe 300mhz or so, so that I can run old DOS games with maximum battery life - rather than DosBox which still keeps my CPU running at 800/1600mhz. I could also run an older OS like windows 98/95 for some exotic game compatibility (one game in particular I know isn't handled by dosbox very well).

Besides this, undervolting is something anyone should be able to do. Acer's got the Atom running with enough voltage to maximize the number of "good" cpus, but if you've already got a good CPU, it doesn't need so much voltage. Suppose I undervolt by 20% or so, it might equate to a 10% gain to my battery life - another 15 minutes of running time, and probably a lot more in standby or even just with the screen off.

 

RMclock will not work on acer aspire one because it uses a new chipset or chip. The northbridge and southbridge and integrated graphic card are all on 1 130nm chip called Poulsbo.

"I'm a pretty hardcore PC user so I'm used to being able to go into the bios and just changing the multiplier or FSB when I want to adjust my CPU's performance, or else change the vcore to help it run cooler if it's overheating, etc. Unfortunately it looks like Acer has (perhaps wisely) kept these features locked up, away from PC-newbie eyes."
All the major PC manufactures keep their bios locked up. It's been like that since god knows when.

"What I'm mainly interested in is seeing how low I can set my vcore before things start crashing. The fan noise doesn't bother me much (I've got 6 on my desktop PC and the one on my other notebook is fairly loud), but I'd love to coax a little extra battery life out of this thing maybe. Helping it run cooler and quieter is just a side-effect... I'd probably also underclock it a bit. For office purposes, 1.6ghz is overkill, and for most other purposes 1.6ghz won't cut it regardless. The most I really want out of this netbook is a portable work processor/web page editor/photo editor, with some old-school game from pre-2000 if I get bored."
The best way to save battery is to turn off your fan and set it to activate at 75-80"C. It'll give you another 0.5-1 hour of battery life on your Acer Aspire One. The fan is rated at 120miliamp @5v. If you run your laptop for 7 hours straight, you'll save about 4W if you turn the fan off. Underclocking the CPU doesn't really give you a lot more battery life. It's already very energy efficient. It idles at 0.2W. If you really care about battery life, you'll have to undervolt the northbridge and southbridge and adjust the vdimm to somewhere around 1.5v. The new Poulsbo chipset allows for low vdimm compared to the standard 2.2v vdimm.

For office purpose, set the battery profile to "maximum battery" and Windows will use the lowest speedstep setting.

"Also if it's possible to change these settings, is it possible to adjust the shared video memory size? I think it's currently at 3mb, which is pretty pathetic considering I've got 300+ mb to spare in all the games I've tried so far."
I think the shared video memory size is 8MB. You don't need a lot of video memory for these kind of laptop. 8MB allows you to play some low end games, do office work, internet, and play 720P HD videos.

 

the newest crystal cpuid version works to underclock and set Multi. Mine runs 1600@1,038 v

 

No, the AAO has an Intel 945GSE chipset. Poulsbo (Menlow) isn't even out yet.

 

Yah, you're right.

 

Did you do anything special to make it work, mine doesn't seem to change no matter what voltage I choose (all are marked with an X)

 

I know in linux there is zero difference in the power draw from the wall when running at 800mhz vs 1600mhz. Is this any different in windows?

 

it doesnt matter if they are x ed... if they are withing specs they should work. try setting the win power profile to desktop but not to mobile/bat, otherwise the windows speed step overrides your settings.