Will this PSU do the job?

Should be fine, what are you wanting to do with your pc?

you should be fine as long as you only have one gpu in there.

I agree with godless. See, the HD3870 uses about 215W under load. Even if you have an AMD 6400+ X2 that uses 125W, assuming no overclocking, you'll still be able to run one 3870 with a 125W CPU, 125W would be the highest wattage possible for current CPU's, and still have about 200W to spare for other components. 200W to spare for all your periphreals is more than enough. However, I would say it's a safe assumption that you will be pushing the limits to use two HD3870's with that PSU. Just the two 3870's alone will be 430W. That leaves you roughly 120W for your CPU and everything else. I would say that's really pushing it. I think most SATA HDD's and optical drives utilize about 10W or so, fans are probably around 5W max, usually not that much. 550W would be good with just one 3870. For two 3870's, I'd go at least 650W minimum. Besides, there will be much better cards are very very soon that will make buying another 3870, or a 2nd of any current generation card (8800GT, 9600GT, etc), very inefficient for the money spent. I'd just leave it with the one 3870 until your next upgrade.

Hope this info is helpful.

--Arson94

Arson94: I dont know where you are getting some of those figures from...

http://www.atomicmpc.com.au/forums.asp?s=2&c=7&t=9354

States that even HD3870 in CF only uses max 163w, maybe your looking at total system load not just the GPU.

OP: The 550w Antec will do you easily, and should actually be able to run 2xHD3870's although it would be cutting it close, and you wont have the cabling on the psu so you would need to use the adapters. Im currently running an AntecTrio650w with overclocked e6600, 7900gt, 8800gt, x-fi with front IO and 3 hdd so your not going to have a problem.

You'll be ok as mentioned w/1 card and not a heavy load
3 12v rails = ,+12V1@22A,+12V2@22A,+12V3@25A
Basiq BP550Plus ~32A

thank you for some good knowledgable responses.

Chookman: what cabling are you talking about on the PSU? its crossfire compatibe so it has 2 6pin pci-e connectors.. unless its something else. also, my motherboard is ASRock 4Core1600P35-WiFi+, its a PCI-E 1.0 unfortunately. I have a 500w PSU right now thats running my system with no problem, but im returning it since i bought the one stated above to replace it. My CPU is Q6600 quad 2.4ghz. Everything runs fine now with no problems, my games, my programs, video editing, etc. Its just that if in the future I will want to add another card i just want to know if it will handle that.

also, kpo6969 mentioned this:

3 12v rails = ,+12V1@22A,+12V2@22A,+12V3@25A

and i have no idea what that means or how to use the numbers stated.

thanks a lot all.

chookman, you may be right. The chart I was looking at had the idle load at like 123W or something like that. I thought it was a little too high but I didn't think to look to see if they were talking about full system wattage under load. It's possible.. My bad, but I don't know if I'd still run 2x3870's with only a 550W PSU. It would still be mighty close.

--Arson94

OP: I was talking about the 6/8pin PCI-e connectors, didnt realise it had 2 your good to go no worries

Arson94: I said it would be close, and personally if i was running 2xHD3870's the last thing i would try and run those new babies on is a PSU that might not be enough...

lol so chookman, we argue that we agree right?

Yeh i think so LOL

can anyone still explain to me what these damn numbers mean though?

3 12v rails = ,+12V1@22A,+12V2@22A,+12V3@25A

one 12V rail is 22amps, the second 12V rail is 22amps, and the third 12V rail is 25amps.

--Arson94

I just wanted to point out to you that 32 amps with those 3 12v figures might suggest 2 cards wouldn't be a good idea.