How much power do you really need anyways?

Atragon · Post by **Atragon** » Wed Mar 24, 2004 1:06 am

I'm upgrading to a new system effectively, I'm looking at:

Mobile XP2500+ (probably with a SP-97 HSF)
1GB KHX3200 (2X512MB)
DFI Lanparty B
Radeon 9800Pro /w VGA Silencer
16X DVD-ROM
8X DVD-RW
80GB Seagate Barracuda.

Now I would have gone for a samsung spinpoint, but I couldn't find any quickly and I got a good deal on the seagate drive, but that's beside the point...

At the moment, I realized that I forgot to get a power supply to go with this system, and while I've got an Antec True380 sitting around doing nothing, I'm wondering if this would be enough juice for this system which I intend to overclock fairly heavily. Some options I'm looking at include the SilenX 400W and the Zalman 400W units, I've also heard decent things about the Vantec ION, but not enough to really convince me to look at it. I'm looking above all for solid voltage with silence comming in a very close second.

Does anyone have any suggestions? Is 400W enough, or should I move up to something like 450W or 500W?

halcyon · Post by **halcyon** » Wed Mar 24, 2004 1:20 am

I suggest the following readings:

http://forums.silentpcreview.com/viewtopic.php?t=3075
http://forums.silentpcreview.com/viewtopic.php?t=9663

My guess is that a high quality 200W PSU would be enough, it may be just easier/quieter (and even cheaper) to find a good quality 300W PSU that does the job as well.

Your Antec 380W should be just fine powerwise, although on the noisy side acoustically.

regards,
halcyon

sthayashi · Post by **sthayashi** » Wed Mar 24, 2004 5:58 am

Halcyon is right.

Machine 1 in my sig draws about 240W FROM THE OUTLET. I can theoretically power it with a 300W power supply. That's with 4 hard drives and 1 DVD+RW

Atragon · Post by **Atragon** » Wed Mar 24, 2004 11:24 am

Cool, so a SilenX 400W should more than do. Cool.

Post by **Ralf Hutter** » Wed Mar 24, 2004 1:23 pm

Atragon wrote:Cool, so a SilenX 400W should more than do. Cool.

Yes, it'll way more than do.

AZBrandon · Post by **AZBrandon** » Wed Mar 24, 2004 5:08 pm

I believe MikeC wrote something about how power supply efficiency drops as it's temperature rises, so that may be a consideration. I did a quick look around but can't figure out where he wrote that. Using a Kill-A-Watt on my own PC's I'll also usually see a spike upon first powering up the system; this can be as much as 50-70% of it's draw at idle, although I suspect that since it's only for a short time, that probably doesn't matter too much. Just a few things to keep in mind. The Kill-A-Watt device is probably one of the most useful tools for things like calculating actual draw at the outlet. I have one system pulling as low as 36w at idle; a figure I had no idea was even possible!

Seal · Post by **Seal** » Wed Mar 24, 2004 5:56 pm

is there a kill-a-watt type device for sale in uk for uk plugs???

Post by **MikeC** » Wed Mar 24, 2004 6:28 pm

AZBrandon wrote:I believe MikeC wrote something about how power supply efficiency drops as it's temperature rises, so that may be a consideration.

It's actually not that simple... More like efficiency actually improves as temp rises -- up to a certain ideal point, then as you push beyond that, it drops, often sharply, as the thermal limits of components are reached. Think of it as something like a bell curve that's steeper on the right side -- past the optimum peak. But you don't get very far on that right side slope down because thermal protection circuitry usually kicks in and stops the PSU.

You see similar things with most machinery, electrical as well as mechanical. Certainly true of cars & engines, audio amps, etc.

sthayashi · Post by **sthayashi** » Wed Mar 24, 2004 6:57 pm

Seal wrote:is there a kill-a-watt type device for sale in uk for uk plugs???

Posted in the General Discussion forum
http://www.maplin.co.uk/products/module ... leno=37708

Seal · Post by **Seal** » Thu Mar 25, 2004 2:39 am

thanks!