How much more power can I cut?

blackbox · Post by **blackbox** » Sat Jun 23, 2007 10:15 am

Hi all, been lurking here for a while now it's time to post!

I've just built (for the second time) a media center pc using the following components.

Antec Fusion
Asus M2A-VM HDMI
A64 X2 3600+, 65w
Seagate 80gb Sata 2.5"
2x512mb Crucial Ballistix
Hauppauge Nova-t + nova-t stick.
Pioneer dvdrom

The aim of this was to get to the lowest possible power consumption but still be able to run vista MCE and keep the cost fairly low, unfortunately my green & cost plans were somewhat screwed up when lightning fried my first motherboard 10 mins after I'd built it, so I've had to replace that.

I'm currently running with the antec PSU that comes with the case, but I'm thinking of swapping for a picoPSU or the 200w version and an external brick.

My current figures are:
Peak boot - 87w
Idle - 52w
Watching TV - 63w

If i take out the dvd rom I knock about 4w off all those figures, so I may do that as I can't see me using it. Unplugging the nova-t stick when not needed knocks a further 5w off. Watching tv without the dvdrom and with only the pci tuner sits around 54w.

How much will the picoPSU realistically cut off consumption?
What about undervolting the cpu?

Any other ideas to reduce its consumption?

Now I have a spare, but partly dead motherboard (pci slots & network port don't work but usb and essentials do) I might have a play with a sempron.

Palindroman · Post by **Palindroman** » Sat Jun 23, 2007 11:48 am

Undervolting will get you another 10% to 35% depending on load. I've got my X2 3600+ running idle at 0.8v and at stock clock speed it's 1.0v (just like the Sempron).

The PicoPSU will probably be very interesting power consumptionwise. I'll have a look at my test results and tell you the difference between a PicoPSU and a 300W SFX PSU from the Antec NSK3300.

Oh, and 1 strip of RAM less gets you another 2-3 watts but you lose dual channel of course.

blackbox · Post by **blackbox** » Sat Jun 23, 2007 2:22 pm

Looks like undervolting may be worth a test then, although load is pretty low I think.

Would be good to see your results from the psu tests, thanks!

Palindroman · Post by **Palindroman** » Tue Jun 26, 2007 7:28 am

Sorry for answering this late.

So, here are my test results for the 300W SFX PSU that's in the Antec NSK3300 (will test the 380W PSU in the NSK3400 this week) versus a 80W PicoPSU with an 80W Edac power brick. You can also see what undervolting brings you.

I would advise a 120W PicoPSU though as the difference between 80W and 120W is negligible.

My estimate is that you can get another 15 watts off (at idle) by switching to a 120W PicoPSU and undervolting the CPU.

dragmor · Post by **dragmor** » Tue Jun 26, 2007 9:07 pm

Palindroman,
A couple of saved watts are probably due to PICO not having a fan. Any chance of getting a reading with the powersupply fan disconnected?

jaganath · Post by **jaganath** » Wed Jun 27, 2007 2:08 am

A couple of saved watts are probably due to PICO not having a fan.

I doubt the 80mm fan in the NSK3300 psu uses more than 1 watt most of the time. The max diff between the two is 13W; the rest of the savings must be from increased efficiency.

blackbox · Post by **blackbox** » Fri Jun 29, 2007 1:13 pm

Palindroman wrote:Sorry for answering this late.

So, here are my test results for the 300W SFX PSU that's in the Antec NSK3300 (will test the 380W PSU in the NSK3400 this week) versus a 80W PicoPSU with an 80W Edac power brick. You can also see what undervolting brings you.

I would advise a 120W PicoPSU though as the difference between 80W and 120W is negligible.

My estimate is that you can get another 15 watts off (at idle) by switching to a 120W PicoPSU and undervolting the CPU.

Thanks for that.
I did give undervolting a try, i can't remember what to (possibly 1.1v) and saw maybe 1w difference. Should i be doing this in the bios or with something in windows?
I'll give it another go when I get some time.

The picoPSU looks good, i think I'll pick one up, about Â£50 for that and a 110v adapter I seem to remember. I'll get either the 120w or the 200w depending on which is cheaper.

Unfortunately my internet connection is still down from the lightning strike so I've yet to use the damn thing, its pretty useless without any guide data.

Thanks a lot guys, I shall update when I finally get chance to finish it off.

Palindroman · Post by **Palindroman** » Sat Jun 30, 2007 1:08 am

blackbox wrote:
Thanks for that.
I did give undervolting a try, i can't remember what to (possibly 1.1v) and saw maybe 1w difference. Should i be doing this in the bios or with something in windows?
I'll give it another go when I get some time.

Use this freeware program. Here's a tutorial. It's a bit outdated but you'll get the gist. Once you undervolt your CPU you'll gain a few watts at idle but a lot of watts at load.

blackbox · Post by **blackbox** » Sun Jul 22, 2007 2:31 pm

Well I gave undervolting another try with rmclock and it wasn't having any of it.

It just BSOD'd and when I did get it stable enough not to die the difference in consumption was a watt or two so its not worth the stability risk.

Haven't gone for a new psu yet, still trying to get the damn thing working correctly. I seem to be replacing everything!

2 Motherboards, bought a usb tuner to go with the pci, but the usb doesn't pick up half the channels so now I need to replace both for a dual tuner, after the lightning stike taking out 2 computers and the network decided to go wireless for the internet, bought a linksys wmp55AG which wakes the pc about 3 seconds after it goes to sleep despite all wake on pci/lan being disabled in bios and windows, now that needs replacing.

Eventually I might get to use it.

Palindroman · Post by **Palindroman** » Wed Jul 25, 2007 7:48 am

blackbox wrote:Well I gave undervolting another try with rmclock and it wasn't having any of it.

It just BSOD'd and when I did get it stable enough not to die the difference in consumption was a watt or two so its not worth the stability risk.

What voltage values did you use? The 3600+ I've undervolted so far went to 0.800v at 0.8 Ghz (4x FID) and 1.000v at stock speed (1.9 Ghz, 9.5x FID) and were stable enough in that they didn't BSOD on me.

blackbox · Post by **blackbox** » Wed Jul 25, 2007 9:19 am

Palindroman wrote:
blackbox wrote:Well I gave undervolting another try with rmclock and it wasn't having any of it.

It just BSOD'd and when I did get it stable enough not to die the difference in consumption was a watt or two so its not worth the stability risk.
What voltage values did you use? The 3600+ I've undervolted so far went to 0.800v at 0.8 Ghz (4x FID) and 1.000v at stock speed (1.9 Ghz, 9.5x FID) and were stable enough in that they didn't BSOD on me.

From memory (and it was a few weeks ago) I used your post above 0.8/1v as a guide to start with and that did bsod, I went a bit higher and it worked till I tried to use mediacenter - bsod, tried a bit higher, saw there was hardly a difference in watts so I decided it probably wasn't worth it.

subsonik · Post by **subsonik** » Thu Aug 02, 2007 1:09 pm

Come on guys, getting a new PSU to save a couple of watts? If you'd really care about green computing, you wouldn't do it. If you'd really care about energy costs, you wouldn't do it either.

If I assume 15W of power savings, 24/7 use, and my local energy prices (about 0.15 EUR/KWh), it would take at least 5 years to earn back the PicoPSU investment in energy savings. The external power brick probably wouldn't last longer than 2 years of continous use - they get awfully hot inside.

Trying to knock off the last couple of watts is nice, if you do it for fun. But if you want to do something for the environment, do something else.