4650 not working with 275 psu - help!

[Milena]

I have a Dell Dimension 9200C with a 275 watt psu.
I purchased a Sapphire HD 4650 w/ 512mb DDR2.
My computer won't boot. Doesn't seem to have enough power but I keep seeing this card recommended for others with slim pcs and little power as well. I am upgrading from ATI X1300.


I'm hoping a bios update will help. Anybody have any other advice before I give it another whirl?

Dell Dimension DXCO61
Vista Ultimate SP2 32-bit
4 GB ram

 

[ubernoobie]

not enough juice in psu if doesn't boot

 

[Milena]

Why does it work for others with the same psu or 250 watt?