I am not the one with the most knowlewdge, just a little bit experience with building. I think Matt is the one with a lot of knowledge. is the processor capable for your motherboard? Right socket and did you look if it can be on your motherboard? ( maybe post your motherboards modelname/number and then we can look if there is a better choice/price processor. ) Graphic card, does your psu have the right cables to connect your graphic card? ( does the graphic card has 6 en 8 pins power connectors or 4 en 6 ?) What is told to me and is a bit experience, a power supply can be 1000watt and still be unstable. A 400 watt can be enough and stable . I always look at the two 12 volt rails ameperage. If that is high enough something like 25 30 amp range. I dont say it is something sciencely prooven, but i learned that by trial and error and a lot of reading about psu`s.
Maybe Matt thinkd otherwise, but he has more experience then me and can be more specific with choosing his parts. Simple reason............he works hard to collect the money for the parts he wants and I have to collect from what comes in ( can be good or just good enough ) So, be more specific about your motherboard, psu, videocard and cooling of your PC. And I am sure there will be an answer.