A new power supply

I am going to need a new power supply for a graphics card, and I need to know if it will be safe.

I have an HP Pavilion a6512p desktop. I'm going to be getting a 450 watt power supply if its safe, so I need to know what the limits are.

Thanks

What graphics card are you getting and what 450W PSU are you considering? Not all power supplies are created equal so links to the GPU and the PSUs you are planning to get would be helpful, as would a budget for the PSU.

Radeon 5570 and the cheapest power supply i can get.

would this one work?

I need a 450W one according to newegg for that card I think

http://www.newegg.com/Product/Prod [...] 6817170014

BAD! VERY BAD!

never ever ever ever go for the cheapest unit you can get. I would go for either the Corsair 430CX that twoboxer linked to or the antec EA380D, both of them would have plenty of power for that system and arent likely to explode spectacularly.
http://www.newegg.com/Product/Prod [...] Tpk=ea380d

The units we are suggesting arent very expensive, $35 after MIR isnt much for a power supply, especially a decent one that isnt going to blow up. If you get that logisys PSU, i doubt your system will survive another year. A super cheap PSU is never a good value, especially one that cheap that shouldnt be more than a 300W unit, its a fire hazard and can kill your system if it goes.

but will those other PSUs fry the motherboard? thats what i was told could happen if I got a PSU that was too strong for the computer.

You can put a 1200W unit into a tiny office PC, nothing bad will happen.

PSUs output a constant voltage, the components draw as much power as they need from the PSU, just because you put a 1200W PSU in doesnt mean that the system will be using 1200W, it justs means it would be able to, the system only draws as much power as it needs exactly at that time.

This is the cheapest psu we here will recommend for you:

http://www.newegg.com/Product/Prod [...] 63938&SID=

Anything of lesser QUALITY could harm your PC, fail prematurely, or fail spectacularly.

If you want to buy something cheaper, you are quite on your own.

The Corsair Builder series is a step backwards. Their old CX line was, but the new ones aren't even 80+ certified. In that range, about the best you'll do is the 380W Antec Earthwatts, which is 80+ bronze and runs very cool and quiet.

Edit: and, as they've said, the PSU is NOT the place to go cheap. You risk your system with a chokemax brand like Logisys. At a minimum, look for full range active PFC (no little voltage switch) and 80+ certification.

Buying a crap psu is like buying a used condom,it will work but its not exactly a good idea