Desktops forum: Periodic Freezing - Possibly Hardware Issue?

Hi guys and girls,

First off, apologies if this is posted in the wrong section. If It is then please point me to the correct forum. I will also say that I'm not entirely tech literate but I know some basic stuff which is what's leading me to believe that this is a hardware issue. I may be completely wrong.

Right, about 3-4 days ago my computer started to randomly freeze for roughly 3 minutes when playing games (Battlefield 3, Diablo 3, and most recently and notabley Guild Wars 2, happens more often in this one). The applications stutter for about 5 seconds and then completely freeze, leaving me with control of my mouse and nothing else (At least it does for GW2, not sure about the other 2). This also causes any other running processes to also freeze (e.g. youtube, explorer etc.). After about 3 minutes, the application recovers and stutters back to life, albeit slowly. This isn't a common occurance but it's enough of a problem for me to post and ask for possible suggestions as to its cause.

The thing that has me baffled is that nothing has changed in the past 3-4 days on my machine apart from MAYBE a gfx card update (pretty sure this didn't happen though). BF3 and D3 worked perfectly fine with no freezes beforehand. I also noticed something which may or may not help. When the applications freeze, my cpu usage drops straight down to about 4% (after running at about 70-80%, at least for GW2). My physical memory spikes to nearly full capacity (around 3.2gb). After the application unfreezes, they return to their original levels, once again albeit slowly. I don't know if this is related or not, just something that I observed.

Anywho, I was thinking it might be a RAM issue. My computer is now about 4 years old and in the past 7 months I've managed to get funds together to upgrade to a new GFX card and Power Supply. My next thing I was looking to upgrade would either be my RAM or Motherboard (which itself is a strange beast o.0). I have friends that have installed both and like I said, until very recently I have not had any issue with either. My aim is to upgrade my machine bit by bit as money allows.

The next thing I want to do is test the RAM with Memtest86 to see if there's any sort of physical problem with the sticks. Once again, however, not being too tech savvy, I'm limited by what I can do to find the solution to my problem.

Here are the specs for my machine (Apologies if any of this is reported wrong, I'm literally copying from a dxdiag and CPU-Z):

OS: Windows 7 32 bit Home Premium
Motherboard: Asus Rampage Extreme 2 http://uk.asus.com/Motherboards/Intel_Socket_1366/Rampage_II_Extreme/ (This one I believe?)
Processor: Intel Core 2 Quad 2.66GHz
GFX Card: AMD Radeon HD 6900 Series (lost the box with the exact name on it, alls I know is that the bugger is bright blue. Will probably update this when I can get into my machine tommorow)
RAM: 4.096gb (can supply make if needed)
PSU: 850w
Page File?: 3590MB used, 5879MB available.

Ok, pretty sure that covers everything. I've done a complete scan of my machine for malware and stuff. Also defragged it. Sorry for the long post, just wanted to make sure that all the relevent information is there.

If anyone has any suggestions then I'm happy to give any more information they require. I will say that practically everything in my machine is factory standard, I haven't overclocked anything or messed with voltages. Also if anyone wants me to do anything like check stuff, please give concise instructions on what to do as once again, not too tech savvy.

Thanks in advance!