I want a 2900XT in the next few months when I up/downgrade to Vista.. I also want the ability to crossfire without having to up the power supply since I've got my wires all fancy.. I'm assuming the 430w Thermaltake TR2 (URL below) will just die.. I know that the PCI-E X16 slot gives at least 50 watts of power so I am wondering which 5.25 inch bay PSU would give me the sufficient power for the future of Crossfireing DX10.. I don't plan on upgrading the mobo/cpu for nearly 2 more years..

(AND is it possible to even use a 2900XT without an additional power supply? whether i have to take out a few fans, disable a hard drive, etc..)

My PSU gives good rails like 11.95 on the +12v, 3.25v on the +3.3v and 5.03v on the +5.0v and if I did get the independant PSU I could see those rails stabilizing to almost perfect.. (it would no longer have to power the Video Card)

====setup====
Opteron 165 @ 2.9ghz w/ 1.4v
Asus A8R32-MVP Deluxe
2GB Patriot DDR400 2.0-2-2-5-1T
X850XT
SB Audigy 2 Platinum
1 SATA CD/DVD Burner
1 80GB HD
1 120GB HD
3 120mm fans
3 80mm fans
1 80mm slot cooler

[if any of you can tell me the amount of power i am using (omiting the X850XT) that would help me out a lot.. I just don't know how to estimate the usage..]

[/url]http://www.newegg.com/Product/Product.aspx?Item=N82E16817153023[url]

This is a link that someone else posted yesterday in another thread. Check this out and it should give you a ball park idea...

http://www.extreme.outervision.com [...] orlite.jsp

Be careful and read what you select very closely. I made mistakes the 1st time I used it so watch out...

your way off

you need a 850 singel rail or 1000w multi rail for 2x hd2900's and room for a hot quad and many drives!

Actually, 90% of the peeps in here will tell u that you don't need that much power even for these specs. Do you think the 2900s use that much more power than the 8800GTX cards? They honestly shouldn't.

Use the calculator on my previous post and it will give you a close estimate on what you need. If it makes you feel more comfortable go a little higher than the calculator recommends. I personally would feel better doing the same but you will have to shop carefully for a decent quality PSU if you are trying to keep the cost to a minimum.