I was wondering whether I can swap out my existing Dell PSU wih another power supply. I have a Dell Studio XPS 9000. I have heard that Dell PSU's are non standard and you can't use other PSU's (i,e, Corsair) without some type of modification/adapter. The existing PSU is 475 Watts so my next question is whats the highest end Radeon card I can use.
believe the only difference between a DELL PSU and ATX PSU is the dell lacks the "on/off" switch in the back (Delluser1 would know better). I have placed ATX PSU into Dell so there is no issue with upgrading your PSU.
The 475w DELL is fairly solid and outperforms a lot of 500w PSU. So you should be good to go on a lot ATI single cards like the 4870, 5770, 5850
if its a mid/full tower dell (not a slim version) then you should be ok, except that sometimes there is some metal in the way of where the switch would be on a normal atx case, because dell psus lack this switch. however, i believe that the wiring is the same as a normal atx psu