thanks everyone for the answers.
about my amperage, the psu is a single rail, so the line has a cap of 53
you're absolutely fine.
12 volts @ 53 amps is 636 watts
now if you notice that is only 14 watts away for the rated total output; it means that is the maximum for just that rail
without including the 3.3 and 5 volt rails. but do not worry; it will not be a factor
unless you want to SLI some power hungry cards like GTX 480s!
your set up needs 245 watts @ 12 volts is 20.5 amps as posted before.