is my psu good enough for 7900gtx. or 2?

[peter2679]

Ordered a 7900gtx and it's on its way. need to know if my Antec neopower 480W is good enough for this card. evga's website says i need 450Watts and 22amps on the 12V rail, but my PSU has dual rails at 18W. The PSU comes with PCI-e connectors. Currently i'm running 2 6600gts with no problems.

Here are my system's specs, if it makes a difference:

MSI K8N neo4 SLI
AMD X2 3800+
2gig corsair platinum
WD 74g raptor, WD sata 250gig
creative xfi extrememusik
plextor px-712

Lastly, when i try to get a secong 7900gtx will that be the time upgrade the PSU.
thanks

 

[OvErHeAtInG]

Definitely enough for 1. Maybe even 2... altho I don't know much about the neopower. Dual at 18A sounds like enough for 2 GTXs if it's a good unit.

 

[peter2679]

how do you compare single rail to dual rail? Is dual rail at 18A equivalent to 1 rail at 36A. can i look at it that way? When looking at power requirements that only give single rail requirements how do i know if my PSU is good enough?

oh, and thanks for the quick reply.

 

[russki]

you cant really combine those, both cards would be on their own 18 amp lines, I would bet anything your psu is ok

 

[Howard]

Originally posted by: peter2679
how do you compare single rail to dual rail? Is dual rail at 18A equivalent to 1 rail at 36A. can i look at it that way?

No. There should be a separate specification for the total combined current.

EDIT: I can't figure out what it is, from the spec sheet. But your PSU has rail 1 at 18A and rail 2 at 15A, so maybe that's 33A combined. I would like to know for sure, though.

 

[Sentry2]

I don't know about 2, but 1 7900GTX should be fine.

If you have to upgrade your psu I would suggest this if you plan on getting 2 7900GTX's:

http://www.newegg.com/Product/Product.asp?Item=N82E16817256006

60A combined on the 12v rails. Silverstone also has an 850W(70A 12v combined) coming out sometime this year. Sounds like they fixed the load balancing issues too.

Oh yeah, those are continuous outputs too. Not max

 

[peter2679]

But your PSU has rail 1 at 18A and rail 2 at 15A,

i don't know where you saw that but on the box it says 18A on each.