A pair of GTX570's will draw about 30 amps together peaking to 40 amps (360 - 500 watts).
The specs in the link say you have a 600 watt power supply. "Peak" power ratings are meaningless.
Next, you have two 12 volt rails, one with a max rating of 30 amps, the other 22 amps. You do not have a max of 52 amps available. 52 amps equals 624 watts - clearly impossible.
The "peak" power rating tells me that you have a relatively poor power supply. I would not recommend trying to power 2 GTX570's.