12V amperage reqs for video cards

[CaptLou]

I am considering replacing the video card in my system to address some video problems I am having in WOW. My system (starting to show its age) currently consists of:

Alabatron PX915P pro MB
P4 520 Cpu
Alabatron 6600GT vid card
1 G ram (4x256K)
1 HDD
1 CDR/W
4x80 mm case fans
Thermaltake Purepower 420W PS

I would like to replace the 6600GT with an ATI X1950 Pro. The documentation I have seen for the X1950 Pro says it requires a PS with at least 30A on the +12V rails. My current PS is spec'd for 18A on the +12V. I have used several of the online tools for computing power supply requirements, and 420W is plenty for the planned configuration, it's just the 12V rail amperage that is in question. I'd rather not lay out the money for a new PS if I don't have too, so my question is, how much margin do the video card makers put into their recommended specs for power supplies? Do they *** a dual card configuration? *** no other changes but the video card, can I realistically hope to get by with my current PS, or to I have to buy a new PS also?

 

[kpo6969]

I would get a new psu, 18 isn't enough. Here's a suggestion 450w @ 33amps

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139003

 

[blade85]

if it does work, it will be a very close call.

 

[randomizer]

Tried running an x1950 pro on 18A, no dice. The above linked PSU is made by seasonic and is excellent quality.

 

[zenmaster]

Perhaps a 7600GT is an option.
More than enough for WoW.

You might be able to use a bit more memory.
Perhaps getting 2x512mb to add to let you up your ram to about 1.5gb may help as well. 1gb is a tight squeeze.

 

[CaptLou]

I expected it was too much too hope for, but it was worth a try. I do plan on upgrading more components (cpu to P4 640, ram to 1.5G), but the vid card is first on my list. I thought about a 7600GT but I don't think the performance increase would be substantial enough, and from what I have seen of Nvidia drivers I would rather go with an ATI this time. Thanks to all for the sage counsel.

 

[kpo6969]

Anything more than a 7600GT you're going to have to upgrade your psu. Ati cards also use more power than Nvidia.