Originally Posted by KJamesJR
If I get the card running at its full potential, will everything else fail on a 550w PSU?
No, the recommended wattage takes into account the whole system not just your graphics card. Trust me, the card does not use 450W or anything like that, off the top of my head i'd guess no more than 200W max under full load (which is something you'd not see in ordinary use), and probably 300W for the whole system as actual
stress test load usage.
Having said that, you want plenty of margin. For one thing PSUs produce less power as they get older and the capacitors age, for another you want to be loading the PSU somewhere near the efficiency sweat spot which will be perhaps no more than 80% load.. then of couse you want room for upgrading.