5750 vs 4850

I have a dell e521 and I am looking to upgrade my graphics card and power supply. I'm not sure wheter to get a 4850 or 5750 but the card must be single slot. Any suggestions for a power supply would be very helpful.

Thanks in advance,
Conor

While i would definatly say the 5750 is the better card, its not true to say it outperforms the 4850 in such a flat statement. The two trade off with each other depending on games and resolutions.
The 5750 is definatly the better way to go unless you dont care about DX11 or are on a tight budget and can get the 4850 at a really good price.
Power supply wise you should be looking at a decent 80+ rated unit of a good make, say Corsair/Antec/seasonic. Something of at least 450 Watts as a general rule with not less than 28 Amps on the +12v rail/s. To be honest though the 5750 should run an a dell PSU anyway. What PSU do you have ?

Mactronix