Hi everybody. I'm looking to upgrade the hardware in my computer to improve gaming experience BUT MOSTLY improve the overall computer performance. I bought this computer 2 years ago and have used it a lot. Recently, the fan that is supposed to keep the CPU cool has been extremely loud and blowing out somewhat-hot-air (causing my room to feel like death during the summer). I just did a manufacture reset on my computer yesterday and it already seems to be running a bit faster, and the fan doesn't pick up as much as it did before, but obviously doesn't run like it was when I first got it or how I'd like it to.

This is the computer I have with all of it's detailed specifications: HP Pavilion p7-1207c Desktop PC Product Specifications | HP® Support

Now a question about the CPU. On that link, it's listed that it has 4 cores, but when I bought this machine, the box said it was a "dual-core". My dad also read on the internet after I bought it that this processor didn't actually have two separate cores, but only one split into two? I don't know if this is true or not.

Anyways, I don't know a whole lot about computer hardware, so I'd like some feedback on what I plan to do and/or suggestions. I plan to install a second fan and 4GB more of ram, but more important buy a new CPU (since this one isn't that great). Is that all I really need to do or should I be looking to improve other hardware? I am on a budget so I'd like to know what would be the most effective option of hardware to replace.

Also, if you have suggestions on CPU's that'd be great. I'm looking for to buy a quad-core processor with a speed of 3.0GHz. But looking at the CPUs that are compatible with my motherboard, these two seem to be the best options. But these are APU's and not CPU's, so are they still compatible? And are APU's a good idea to use instead of a CPU in my case? I don't know the complete differences.

Amazon.com: AMD A8-3850 APU Quad-Core Processor (AD3850WNGXBOX): Electronics

or

http://www.frys.com/product/6930167#detailed