Whilst no one truely knows the power requirements of the 8600 series, I would imagine a 250W PSU would be 'pushing it'. To be honest, you should be running off a 350 - at the least. That should give you a bit of headroom.
Hmm, based on the picture on the reference board it doesn't have a power connector... while previous gen cards like the 7950.. even the 7900GS need external power.
Maybe this newer gen card might have lesser power requirements than the high end 7 series ... (e.g. 6800 vs. 7600GT).
You are about to answer a thread that has been inactive for more than 6 months. If you still wish to proceed, please ensure that your posting is original and does not duplicate or overlap any prior responses to this thread.