Right now I have a 480W PSU that has 20A on a single 12V rail.

I am getting an 8800GT on friday which I believe recommends a 26A rating. Now I am not a computer whiz be any means so I'll post an relavent info I can think of about my computer and then you can tell me if my current 480W PSU will be enough.

AMD 64 X2 5200+
M2NPV-VM motherboard
3 sticks of DDR2 (3 gigs)
Asus 8800GT
CD drive
DVD drive
couple of USB devices
Only cooling fan I have is attached to the PSU
My current card is a Saphire X1650pro 512 PCIE

Now how much of that is useless info, I don't know but I figure the more info the better.

So will be current PSU be enough or will I need an upgrade. If I am able to stick with my older PSU when should I look for to indicate a problem?

nope

So what should I step up too?

A guy at the store I am getting my card from recommends a 585W PSU. It has 2 12V rails at about 20V each.

Is that enough?

yes

Can someone else verify this? I was told be another forum that my old PSU would be enough.

I don't squat about power supplies really so I am kinda lost without some solid advice.

Choose one from Tier-3 or better from the list at http://www.tomswiki.com/page/Tiere [...] ngs?t=anon

Anything less and you're asking for a cheap sparkler that may take other things with it when it dies.
FSP makes some decent ones at the lower end of the price range, but you'll still probably spend $58-$65 on one.

You might squeek by with that PSU. But you shouldn't be surprised if it turns out to be a problem either.
No reason not to try it and and see how it goes. You'll know pretty quick once you start a heavy gaming session.
It maybe that your gaming sessions aren't as GPU taxing as some other games/systems might be.

A bit out of topic....

But I noticed you are running with 3 sticks of DDR2. AFAIK that means you are running at half the bandwidth.

Correct me if I am wrong anyone.

A Corsair 450vx would do the job without breaking the bank. Around $69 after rebate.

Of course it will be sufficient. Dont believe everyone who tells you how powerfull PSU you need. I just built a PC for my friend (C2Q @ 3,6 GHz beast!, 8800GTX, 2x1 G RAM, 3x HDD and many many fans, running on poor 450W ASUS PSU). Even if your PSU would be really crapy, with 480W rating it should be fine

Gotta love the one word answers that dont describe, suggest or imply anything. Is this a way of getting around being wrong?

As WR2 suggested you may just sneak in with this PSU but after capacitor age and wear on other components it would be safer to buy a quality PSU. Almost anything from Antec, Thermaltake, OCZ, Corsair, FSP, PCPC will run this system. If you are considering upgrading a little more in the future id suggest paying a little more so the next time round this wont happen. Corsair 520HX is a good unit with modular cables 620HX is dearer with more power for future. If you dont want to spend that much look at the 450VX that tlmck suggests or thermaltake/FSP unit as they are generally cheaper with still quality components.

20A on a 12V rail is 240W. I don't think your entire system can consume that much DC power unless you start overvolting the CPU.

Hoping my post will be helpful, but I'm not too confident.

I don't know very much about PSUs, especially when it comes to rails and all that. BUT, I dropped in an 8800GT on my Dell e521 just last week. I had a 300W stock Dell PSU, which I've read performs well and can pump out 350W. I didn't notice any slowdowns, Call of Duty 4 ran great at all high settings. Obviously all Vista scores and 3d Mark Scores doubled, upgrading from a 7600GT.

To be safe and also just because I wanted to, I put in a 470W PC Power & Cooling PSU. I don't notice any performance increase, but my 3D Mark Score did jump a bit in all categories (100 points or less)... so it probably provided *some* improvement and is probably better overall for the machines components.

I might be comparing apples to oranges here, like I said, I'm clueless about rails and all that... so I don't know if my original PSU was single or double or compares to what you're currently running. Anyhow, if we're talking about the same thing I'd say 480W is more than enough... because my 300W was working fine.

It's very probable that the most that your current setup will need (with the 8800) is about 350 watts. Even the baddest, most power hungry SLI quad rigs don't use more than 550. That being said, you should be concerned about the amps and quality of your PSU. If the card manufacturer says that you should have at least 26 amps on the 12v rail, then you should probably listen. Your card will run slower during heavy gaming, your system will be unstable, you may get artifacts, you won't be able to overclock, etc. Before I bought a quality PSU I noticed these problems.

Also, getting a quality PSU can have a significant effect on the performance of your pc. Or, rather, having a garbage psu can be significantly detrimental to the performance. Unstable and highly fluctuating power supplies can kill a good system, ruin performance, blow things up, impregnate your daughter, and the list goes on. There's no reason to have a trash psu in a good system, it's just not worth the money you might save.

Rather than worrying about watts, worry about quality and amps. Watts are just a marketing ploy, no more.

Wattage is just one requirement for a modern system. It is also about having enough amperage on the 12v rail. Even though low wattage, Dell's are actually pretty good on the amperage. Your 300 watt would have burned out before long though due to being stressed to the max all the time. You should be fine with the 470.

Keep in mind also, that most of the newer components coming out will draw less power than their predecessors, so you should be really fine for some time to come.