Hey there I am abit of a noob with computers and I just want to ask something. The HD 6670 Graphics card has a minimum power requirement of 400W. Today i checked and PSU only has 300W. Do i need to get a new PSU or can i just use this one? The card i currently have installed is a 5670, and i think it also uses 400W, but i am not sure, i do not have the box with me(its a 512mb GDDR5). I heard somewhere they overstate the power requirement of GPU because of some crappy PSU manufacturers?
The HD 6670 actually uses slightly less power than the HD 5670. Therefore, your current 300w should be fine. Power requirements are "overstated" because they don't exactly know what is in your PC. A Core i5-2500 uses less power than a FX-6100; some people may have more hard drives than other people, there's lots of variables. Also most people have average quality PSUs, many have sh*tty PSUs, and a few have good / excellent quality PSUs.
You should know that the HD 6670 is only about 10% more powerful than a HD 5670. Therefore, it is not much of an upgrade in my opinion and I would not bother upgrading. The Radeon HD 7xxx series should be released early next year, I recommend waiting for the HD 7670 which will probably use around the same amount of power as a HD 6670 / HD 5670. Even if it is only going to be 10% faster than the HD 6670, that basically means it will be 20% faster than the HD 5670.