2 +12v rails and 1 graphics card

The card doesn't require 24 amps, it is reccomended that the psu in the system you intend to put the card in, provide at least 24 amps ( doesn't matter if it's single or multi rail ).
Look at the label of your psu
http://www.newegg.com/Product/ShowImage.aspx?CurImage=1...
The combined 12v ouput is 360 watts or 30 amps.

so what is the advantage of having a huge single rail? also, sorry if this is a stupid question but how did you get 30amps, I cant find it on the label, it only shows 2 12v rails 18a each and 360w combined.

well, 360/12 = 30.. high school physics  

Anyway.. A single large rail does not really add much over a well built multi rail system. Though the first few multi rail systems were not set up very well and did not always both send multiple leads to a particular line, sometimes you would only get 18A (or whatever a single rail would be) at the PCIe connection.

PSU companies will go on about how single rail is more compatible blah blah blah, but so long as you are getting a quality unit it doesn't matter.

thanks, i remember now, i just though that combined output of 2 rails is found by adding them, but 30amps is more then enough for my setup anyways