On there you can see that the 5900XT is 250 bit like the 5900 and up cards. Get one of the better brands and most of them will overclock to the same speeds as the higher priced cards or at least very close to it.
I'm not really concerned with clock speeds and overclocking potential. I need to test a development bug and was hoping to get away cheap. Something about rounding errors in the FX chipset.