Are ATX power supplies all the same physical size?

[Charles Elms]

I have to replace my son's Presario SR2180NX power supply to get more amps for a new video card. The old one is only 300 watts. I've located power supplies with 550 amps and it's an ATX 'form factor'.

 

Should it physically fit in the Compaq?

 

Thanks in advance.

[Charles Elms]

FYI.

Power supply replaced. It fit, but was a couple of inches deeper into the case. The cable bundle was at a different location creating a super tight fit behind the CD. It's together and working.

[stubble!]

Yeah, there's no real spec on depth, and it varies. Sometimes width too. The bolt pattern is the same for all, but there can be variation in size. Glad you got it sorted out.