How to know what kind of power supply you need when upgrading you pc

[elizanaomi]

Hello, I'm looking to upgrade my graphics card to something a bit more powerful than what I currently have. However my computer only has 300 watt power supply currently which as far as I can tell (I'm not too great with this stuff) isn't exactly adequate for many gaming cards.
So I was wondering what kind of power supply I should get to support a better graphics card
I'm running Gateway DX4840
4GB ram
575gb HDD
nVidia GeForce GT 320
Intel quad core i5-750 @ 2.67GHz

Any help would be greatly appreciated

 

[13thmonkey]

when you've figured out what card you want, there'll be a recommended minimum 12V amps for that card given a normal configuration (which you have), this then informs choice.

Go for a good quality supply, that meets those requirements.

So what card do you want?

 

[elizanaomi]

I was looking at something a bit cheaper but that could still run things for me, like the nvidia geforce GTX 260

 

[elizanaomi]

Or possibly looking at an ATI Radeon HD 4890 1GB

 

[13thmonkey]

Does you gateway supply say how many amps it has on 12V?
and from your research do you know what those two cards use ?
Why going for such old cards? what is your budget?

 

[chiptouz]

I always go to this website and when I am done with what I think I want. I pay the $2 to make sure that my rails can handle the load that is being placed. Go to google and search for extreme powersupply calculator. They have all the up to date vid cards, processors, etc.

 

[13thmonkey]

you can do it for free in many places.

 

[chiptouz]

Probably so multimonkey, I just have experience with the one I referenced.

 

[ko888]

For a system using a single GeForce GTX 260 graphics card NVIDIA specifies a minimum of a 500 Watt or greater power supply that has a combined +12 Volt continuous current rating of 36 Amps or greater and that has at least two 6-pin PCI-Express supplementary power connectors.

For a system using a single Radeon HD 4890 graphics card AMD specifies a minimum of a 500 Watt or greater power supply that has at least one 6-pin and one 8-pin PCI-Express supplementary power connectors.

Since your Gateway OEM 300W power supply unit is grossly insufficient for either card and it also doesn't have any PCI-E power connectors and only has one 4-pin Molex connector you must upgrade the power supply unit.

The following reputable brand power supplies will have no problem powering either graphics card:

The Antec Neo ECO 520C for $54.99, with its +12 Volt continuous current rating of 40 Amps and with its one 6 Pin PCI-Express supplementary power connector and one 6+2 Pin PCI-Express supplementary power connector meets the requirements.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371030

XFX Core Edition PRO550W (P1-550S-XXB9) 550W for ($54.99 after mail-in rebate card), with its +12 Volt continuous current rating of 44 Amps and with its one 6 Pin PCI-Express supplementary power connector and one 6+2 Pin PCI-Express supplementary power connector meets the requirements.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817207013