Well I actually had EVGA 750 novas from my thunder X6 Zeus miners. So I had 6 of those. I clock all my s3's to 500ghz so that draws +/- 400w , so I went 1 psu for 1 s3. Then on second shelf I used (1) EVGA 1300W to power 3 overclocked s3+'s . Works like a charm. Each shelf held (6) S3+ . Top shelf I used the evga 750 I had on hand from the zeus and did 1 for 1. 2nd and third shelf was (1) 1300w evga for 3 overclocked s3+ B11 @ 500ghz stable. Power supplies mounted under the 3s's. Heres some better shots: