GTX 260 power question

I have a 550W PSU from Chieftec. It has three 12V rails, 18A each (3×18=54A). Now I want to buy a Geforce GTX 260 that requires a 500W PSU and 36A power on 12V. I suppose my PSU will be fine, these 12V rails should self adjust ?? Funny thing is, the PSU only has one PCI-E cable with two 6-pin connectors.

http://www.chieftec.com/smart-power.html

It should work, but bear in mind that 3 18A rails do not necessarily give you a total of 54A. Generally, this is just the maximum amperage one of those rails can handle. My PSU has 3 16A rails, but if you read the sticker more closely, the max output across all three is only 32A (not the combined total of 48A).

As I said, it oughta be OK, but you'd do well to check the sticker on the PSU again and see if it gives you a total output across the 12v rails - if it follows the same pattern as mine, it should come to exactly the 36A you need, which would be cutting it a little close if you have a lot of other stuff in our system.

Just bought the card and it works. Thank you all.