400w psu is just about right to support two GTX 1050ti in your pc. basic online psu calculator: Load Wattage:353 WRecommended PSU Wattage:403 W [IMAGE]
[IMAGE]   So I have a dell optiplex 790 minitower with a low profile 1050ti but I have a single fan 1050ti lying around aswell. Was wondering if I could plug it in aswell? I have a 400 watt PSU and 16 gigs of ram, Intel i5 2400 (pic of the GPU included aswell) 
Dual GPU on Dell optiplex 790 minitower?