EVGA 9800 GTX+ 18A vs. 24A Power

No it's not a big deal, the power reccomendation of 24 amps is for the entire system not just the card.

Dude, hold on. I think DellUser mis-spoke when he said the 24amps was for the whole system.

You said it is on your card's box. That means your graphic card requires 24amps for worry-free performance. This is quite common. Most high-end cards today require 18-30amps. They may not use it all the time, but could need it. Don't rob them of what they need yet demand them to perform the same. If your power supply cannot deliver 24amps, it will deliver the 18 it can, but your card will run hot.

I doubt seriously 6amps too little will cause problems, but anymore, and you could ruin your card over time.

I just did this with my 8800 which required 30 and I had no idea. My PSU only gives up 14amps to each 12v rail. It was not enough. My card worked fine for months (even gaming) but eventually died after a year.

I hope some others will also reply and re-affirm what I'm saying here, so take what one person says here with a grain of salt, but do be careful. Monitor your temperatures closely especially while gaming.

For reference mine was an 8800GTS OC with 640MB ram. I think it was going to run hot no matter what but low voltage and barely enough PSU surely didn't help it either.