Is the graphics card the only thing the psu runs?

[Leuce]

The graphics card I bought needs 300 watt and my psu is 300 watt. If my other components need power too, I'm fucked. D;

 

[AgentTran]

No, your PSU powers all components in your supply.
Could I ask what PSU you have and what GPU you have?

 

[InvalidError]

The PSU usually provides power to everything inside the computer case.

What is the actual GPU? If we are talking about a R7-240/250 or similar, the 300W "rating" is for the whole PC. For GPUs that require somewhere close to 300W, you need to look at very high end models like the R9-290X and equivalents.

 

[Leuce]

Gtx 750 and 300 watt power supply

 

[Mouldread]

Here you go:

http://extreme.outervision.com/psucalculatorlite.jsp

Use this, fill in all the info and it hit calculate to see what PSU you will need to power up your entire PC. Everything draws power from the PSU - CPU, fans, GPU, DVD-ROM, USB drives and what not.

 

[InvalidError]

Gtx 750 and 300 watt power supply

The GTX750 is a ~60W card. The rest of your system likely uses less than 100W unless you used some surprisingly high-end/high-power components for the rest of it.

There aren't many high-quality 300W PSUs out there so you might want to be more specific about that - poorly designed PSUs can fail or misbehave, sometimes catastrophically, even at a fraction of their "rated" load.

 

[boosted1g]

300 watts is enough to power the card and the computer. Unfortunatly as others have said that most all 300 watt psus, including the ones in OEM computers, are not very good quality. They are not made with quality parts for longevity, and if they are really cheap then that 300watts is a mystical number that it will never achieve until 2 seconds before it dies and takes all the other parts with it.

PSUs also degrade over time, lookup capacitor aging, and thus even a quality psu will not be able to power a system at max forever and in a few months to a year wont be able to do it anymore.
The best budget PSU in the range you need right now is the Antec Basiq bp430. FYI the corsair cx430 has had many issues with it not lasting more then a year so it is no longer suggested as a good cpu.