for my upcoming S3, I had ordered a Segotep GP700G (600 W total)... 48 A & 576 W on the +12V rail... it can provide enough juice for the S3...
an update, since, there was no stock on the Segotep GP700G PSU, I changed and purchased one Antec NeoEco 650M (650 W total)... 50A & 600W on the +12v rail... both the S3 and the Antec NeoECO 650M are running 24/7 now... also, I had purchased one Segotep RP Plus 650 (550 W)... 45A and 540W at the +12V rail... its now waiting for my 2nd S3...