G Protein :
Thanks for your reply. I was wondering if I should use a 600W or 650W PSU? I hear conflicting thoughts across the internet.
There are varying opinions on Tom's about this subject. The CPU and GPU consume most of the power in a build and for a single GPU build many say that 500W - 650W PSU is sufficient and in a sense they are right, especially with the 650W.
Most CPU and GPU combos draw approximately 300W. It might drop as low as 250W in with smaller GPUs and slower CPUs. Peripherals like an optical drive, a CPU cooler, RAM, motherboard and case fans also draw power. I like to be conservative and allow 100W for these. Please understand these are rough approximations. You can easily do the research to find the exact wattage your particular build will use if you want to take the time to do so.
So we for a single GPU non-overclocked build our rough estimate is a maximum power usage of 400W. This means a quality 600W PSU will carry the load as will a 650W PSU and many builders on Tom's have gone this route and had not problems.
There is another factor to consider and that is efficiency. The more efficient the PSU, the less power it will consume and the less noise and heat it will generate. Nearly all PSUs run most efficiently at 50% of their maximum power usage. Therefore if we wanted our PSU to run at approximately 50% capacity (50% of its wattage rating) we would specify a 750W or a 850W PSU (there doesn't seem to be an 800W category). This is the route that I chose. For my single GPU build I chose the Corsair HX 850 which is overkill because I will only be using 50% of its power. However I am running at nearly 92% efficiency which is about as high as you can get.
So which is best? All of them work - so all of the choices are good. If you have the money, I would recommend a Corsair TX 750 or a Corsair HX 750 or a Corsair HX 850. However you mentioned you are on a budget and it is also a good choice to go to the Corsair CX 600 or TX 650. So the answer is if you want the best efficiency spend the extra $75 - $100 for a more the 750W or 850W PSU.
One other thing, if you are going to get into gaming seriously and use two GPUs in crossfire or SLI, then I strongly recommend that you get the Corsair HX 850 - it is the perfect PSU for a two GPU build. This is one huge advantage to buying a larger PSU, it will last several build and can handle more components. The Corsair HX 850 has a 7-year warranty.
If money is tight, just get the CX600. It is cheap enough so that you can upgrade to a larger PSU later and not lose a lot of money.
One last thing, try to get the modular version of the CX 600, modular PSU are MUCH easier to build with. Modular means that you can add only the wires you need for your specific build. Non-modular all of the wires a combined in one big mess and you don't have a choice.