Serious overheating issues

[Silverthing]

System:
500w Coolermaster PSU
4 GB DDR3 Ram
MA74GMT-S2 Motherboard
Athlon x3 450 (Unlocked)
XFX 5770

Hello, first of all, sorry if I've posted in the wrong place. I've been having some serious problems with my Motherboard / CPU overheating. My (What I presume to be my northbridge) goes up to 100 Degrees and then my computer cuts out without a BSoD or any warning.

While idle my computer is fine, however when I play games such as Battle Field: 3 I have issues with it. It used to happen on Counter Strike: Source but since the installation of a 120mm fan it seemed to have stopped on it / being very occasional. I've put new thermal paste in with a couple of degrees difference, nothing particularly helpful.

Idle:

I have another 120mm fan however if I put it into my case it has to go on one of the sides, which I always have open. When putting it there and having the side on the computer gets too hot and actually is higher than if I didn't have the fan there at all.

Any suggestions of what I should do? I currently do not have the money to get a new motherboard so that's out of the question for me at this time.

 

[grassyuk]

Submerge it in a bucket of thermal paste.

 

[rgd1101]

undo your unlocked core and check the temp again.

 

[Silverthing]

I've already tried that, I think the biggest problem is my northbridge, it didn't make much of a difference.

 

[smorizio]

try picking up a northbridge chipset cooler. if not it may be your chipset may be on the way out.

 

[grassyuk]

Buy a potato and crush it into the heatsink