power supply is 250 watt but it's a Dell so it's probably closer to 300 watt.
the card slot is a pc-i and not agp.
self-correction..
THe 170L SFF only has pci so that is why recommended a nvidia 6000 series (last PCI series I believe).
The 6200 is the cheapest.
The 6600GT or 6800GT would definitely be better but in PCI they would be hard to find and pricier though a 6800GT would breathe
some life into that machine
His PSU should be able to handle it.
My Dell Precision 450 360watt PSU powers 2 IDE HD,two DVD-RW,Nvidia 7600GS,PCI Cooler,Two CPU's,80mm case fan,Audigy 2 EX Platinum sound card
and assorted USB devices (USB TV Tuner) and that PSU is original (2004) to case.
The Dell PSU's back then at least were underated.