Monitor shutting of during gameplay

[lemiesz]

my computer specs are the following
q9300 2.4ghz quad core
4gb ram
BFG tech 9800gt 1gb memory

It seems that everytime i play a game weather it be something moderately intensive such as spore or very intensive such as crysis, my monitor will shut off. Im am suspecting overheating because when i look at the speedfan readings im getting around 70-80 C on my gpu and 60-70 on my Cpu. But im not sure which of these is actually overheating because i remember my old 8800 would reach up to 100+ C and still run. But currently to remedy this i have put a giant fan next to an open case and it seems to help.

My question is how is what exactly is the problem and how do i fix it for good

 

[Route44]

Yes, it certainly sounds like a heat issue. Have you looked up the temperature threshold for your 9800GT?

Consider this: 70C = 158F

 

[joeflint82]

If both are running that hot, I would be thinking about case ventilation.

What information can you give on your case ventilation?

Do you have working fans at the front (blowing in) and the rear (blowing out)? This would be a minimum. They regularly clog up with dust on my machine, I use a vacuum cleaner on them every month or so.