Hi there. I'm working on upgrading my Dell Optiplex GX280, and for my present purchase decision, I'm working on upgrading the video system. This will require a new power supply, as the standard 250-watt certainly won't be anywhere near enough.

Presently, the system contains:
Pentium 4 540 3.2 ghz
4 sticks of 512 meg DDR2 ram
1 SATA HDD (160 gb maxtor)
1 Floppy Drive (though I don't ever use it, and am considering just not connecting it to the new PSU)
1 DVDRom/CD-RW combo drive
Sound Blaster X-Fi Platinum (upgraded to that last year, it's the one with a front-bay)
Radeon X300SE

So, I want to upgrade to a 7950gt. Now, I read through the "PSU 101" guide, and after running the calculator on the CPU, HDD, DVD drive and Video card, I come up with 235 watts, with 19.58 amps needed on the 12v rail. However, I'm not quite sure I fully understand this, so please bear with me.

I was considering the following PSUs for the system, though after these calculations they would seem inadequate:

Sparkle 350-watt
http://www.newegg.com/product/prod [...] 6817103012

Coolmax 400-watt
http://www.newegg.com/product/prod [...] 6817159045

Neither of which has the required ~21 amps. So, if those are indeed inadequate to fulfill my power needs, could anyone make a reccomendation? I'm still looking around the 350-400 range, but I'm having trouble finding one that says it's rated around 20 amps on the +12V rails. Should I be looking up in the 500-watt range for that kind of amperage? BFG's suggesting a 350-watt with 22 amps on the +12V rail on their page for the 7950GT, but it's proving difficult to find such a PSU.

I'm a very heavy gamer, also, though I don't know how much that factors in.

I'm new to this whole power supply thing, and to building PCs in general -- figured I'd start with upgrading an already-built rig first as I finish out my college career. Thanks in advance for the assistance.


UPDATE:

After some more searching, I've found the following:

Enermax 300-Watt
http://www.newegg.com/Product/Prod [...] 6817103463

with 22 amps in the +12V. I took the calculator and threw in my entire system, and I come up with 282 watts; and after taking the 235 watts of before and adding 30%, I get 305.5 watts. I only plan to be using this thing for about a year, at which point I'm probably going to rebuild from the ground up... so am I correcting in thinking that this might be my answer?

Hi KaiserWarrior

For our machine builds we have been using Antec TRUE POWER TRIO 650 WATT TP3-650 GB PSU.
Antec also do a 550 model.

One of our current Test Systems is spec'd below.
Antec TRUE POWER TRIO 650 WATT TP3-650 GB PSU
Asus M2N32 WS Professional
AMD Athlon 64 X2 5200+ AM2
ThermaTake CL-P0268 775/K8/AM2 MINI TYP RET
Corsair 2GB XMS2-6400 C4
XFX Geforce 7950GT 570M
2 x Western Digital 150 GB Western Digital Raptor
Seagate BARRACUDA 7200.9 500GB 16MB
2 x Plextor RTL PX-760A
Creative X-Fi Extreme

Runs almost silently - great for gaming - I've tried

You will need to make sure the PSU has connectors for PCI-E Graphics cards (2 come supplied on the Antec PSU).

Also for future growth you may want to a consider a Crossfire or SLI certified PSU as avid gamers can never have too much GPU power

Hope this Helps and Merry Christmas

Compulsive Computing

http://www.compulsivecomputing.co.uk

Thanks for the suggestion, but that Antec is a little beyond what I'm looking for... I should have been more clear in my original post.

Future expandability is nice, and I'll be looking for such a thing about a year and a half from now. At the moment, I just need something that will power my current system with that video upgrade, and if I can stick around the $50 range and pull it off, that'd be very nice. A $100 PSU is a little pricey for me, especially considering it's got THREE 8O rails -- overkill for my little 1-HDD, single-GPU system. As it is, my current monitor only goes up to 1024x768, so SLI does nothing for me.

The idea is that, when I've got my college expenses behind me, I can get the guts for a new system, but carry over my GPU and Sound card to tide me over until DX10 becomes a real standard; so I don't need anything more than what a 7950gt would require for the moment.

Again though, thanks for the input; I'll keep it in mind for future upgrades.

I have a Tagan black 380 watt. Its got 22A on the +12V rail, and a molex connector specifically made to be attached to a GPU.

Im running :

P4 2.5 Ghz (will be changed to core 2 in a month cause the current one is one hell of a bottle neck)
2 sticks of 1Gb ram
2 DVDRW drives
1 Floppy drive
2 HDD ( 80 + 250)
Sapphire X1950 pro 512mb
and a few external stuff that get their power via USB

I havnt had any problems with it yet also its not very costly so it wont bankrupt you.

some info about it: http://www.rackmountnet.com/ps/tagan/tg380u01.htm

Get the FSP Group (Fortron Source) AX400-PN 400w PSU. It comes out to $49 including ship and provides 25 amps on the 12v rails.

http://www.newegg.com/Product/Prod [...] 6817104953

FSP makes better PSUs than Sparkle and Coolmax.

Thanks a lot folks, these suggestions are just what I was looking for. Very helpful community around here

I second the Antec Truepower, I have the 550w version and a 7950GT KO, works great. But the FSP mentioned looks like a very good deal if you know you won't upgrade for a while.