You should stick to what the card Mfr says it should be. i.e. someone said 450 watts. I agree with that for a GTX 750TI. I have used an EVGA 730 GT in an HP Compaq Elite 8300 SFF with a 240 watt PS. It started up and looked great until the PC started having USB issues. And I think that card just required a 300 watt PS. Power messages every now and then about the USB 2.0 hub. Then I noticed audio would go in and out using a Blue Tooth headset that was connected to BT via a small USB device. Never had issues before until the new card. Droid phone connected fine.....for 10 minutes or so until the pc complained of power issues.The video was great, though. YMMV so be careful.