Good graphics card

[tj_extreme]

Nvidia recommends a minimum PSU of 400w for the GTS 450.

 

[PP Mguire]

Sorry just one more question If my current PC only uses 170 watts (about) could i get a GeForce GTS 450 that says it uses max 106 watts and not destroy my psu?[FONT=Trebuchet MS, Arial, Helvetica, sans-serif]s[/FONT]​

You have to understand that even though your PSU says it is 300w, that is the maximum capable unless it is 80% Plus certified. Good PSUs have a relatively high headroom and can go over the wattage but to run your PSU for long periods of time that way will fry it quickly.