Upgrading graphics card, PSU too?

[aianta]

hello,
I am upgrading to a nvid Gforce 570 link here:

http://www.futureshop.ca/en-CA/product/zotac-zotac-gtx570-1280mb-gddr5-pci-e-video-card-zt-50201-10p/10166984.aspx


The min reqirments say I need 500 watts of power.

I have 3 questions:

1) What happens if there is too much power on the supply? ex I get a 600 watt one.

2) what specs should I look at for in a power supply?

3) what prices should I look for in a power supply?

Thanks, in advance

 

[Gulli]

1) Nothing bad, the PSU only supplies what the components need. When you have a 1000W PSU in a PC that only draws 300W, the PSU may be somewhat less efficient than a 400W PSU, but there will be no ill effects.

2) 80 plus certificate, lots of power on the 12V rail(s), this is indicated on the side sticker of the PSU (amperage (A) times voltage (V) equals power (W), my personal rule of thumb is that the combined "TDP" of the PC components should be less than 80% of the power the PSU can deliver on the 12V rail(s)***), look for a large fan (12cm) because those are more silent.

3) As long as the consitions of 2) are satisfied just go for the cheapest.


*** for example: you have a 95W TDP processor (maybe an Intel core i5), one hard drive (~10W TDP), one DVD burner (~20W TDP), the Nvidia GTX 570 (220W TDP and two colling fans (2W each) inside your PC. Then you need 349W*(10/8)~440W on the combined 12V rail(s) to be completely on the safe side, and remain there for years to come. The DVD drive won't usually be spinning while playing a video game, but it's nice to have an extra margin. There are other components like system memory but those require very little power and don't draw from the 12V rail(s).

 

[aianta]

Thanks for the quick reply.

According to this power output calculator, I need a 422 watt power supply. So keeping your rule in mind I went looking for a 550watt power supply (550 x 0.8 = 440). I think that should give me the margin that you were talking about.

Im not sure about any of the other specs so here is the link:

http://www.futureshop.ca/en-CA/product/rocketfish-550-watt-pc-power-supply-rf-550wps/10110949.aspx?path=6779b8ee350114fc0b466bda8880f146en02

Thanks again

 

[Gulli]

Thanks for the quick reply.

According to this power output calculator, I need a 422 watt power supply. So keeping your rule in mind I went looking for a 550watt power supply (550 x 0.8 = 440). I think that should give me the margin that you were talking about.

Im not sure about any of the other specs so here is the link:

http://www.futureshop.ca/en-CA/product/rocketfish-550-watt-pc-power-supply-rf-550wps/10110949.aspx?path=6779b8ee350114fc0b466bda8880f146en02

Thanks again

Well, the total wattage is not as important as the 12V wattage: look for a PSU with at least 430W on the 12V rail(s) and with an 80 plus certificate, like this one: http://www.newegg.ca/Product/Product.aspx?Item=N82E16817341022 or this one: http://www.newegg.ca/Product/Product.aspx?Item=N82E16817139028

 

[FlintIronStagg]

Corsair or Coolermaster are great brands for the 80 plus cert. and remember - you get what you pay for with power supplies cheap means cheap

 

[aianta]

My last question is are there different physical sizes for power supply or will they all work with any tower computer?

If there are different sizes how can I find out what size I need.

 

[aianta]

Best answer selected by aianta.

 

[Gulli]

My last question is are there different physical sizes for power supply or will they all work with any tower computer?

If there are different sizes how can I find out what size I need.

There are two sizes I know of: the regular kind that fits in normal towers and a smaller variants for those small office PC's. You'll want the regular kind and I'm not sure if they even sell the smaller kind, except to companies like Dell.