PC shutting down in Games after 5 mins

[GashCustard]

Hi my PC is doing a hard shutdown whenever I load a game. this usually happens within 5 mins. Can browse the net and watch vids fine its just for games.
My PC is
Intel Core 2 quad Q6600
8gb ddr2 ram various brands.
Msi GTX660 twin frozr
Not sure what brand psu is but it's 750w.

I know its nothing to do with overheating as even under full load cpu doesn't go over 50 and GPU over 60. Please help

 

[Cons29]

check your temps, monitor them esp when gaming,try msi afterburner or something similar.

if those are ok, it may be your psu, try a different one if you have (or can borrow) a spare.
also, if you can find out the brand of your psu, it would help us also

 

[Stuart Martin]

My PC did the exact same thing, turned out it was restricted airflow to the graphics card fan. Sorted that and it was fine. I could browse the net etc as the load was low but as soon as a game loaded and the GPU was put under more load, it would shut down. I'd check the fan and/or airflow

 

[GashCustard]

Hi my PC is doing a hard shutdown whenever I load a game. this usually happens within 5 mins. Can browse the net and watch vids fine its just for games.
My PC is
Intel Core 2 quad Q6600
8gb ddr2 ram various brands.
Msi GTX660 twin frozr
Not sure what brand psu is but it's 750w.

I know its nothing to do with overheating as even under full load cpu doesn't go over 50 and GPU over 60. Please help

It's definitely not the temps or air flow. I had the CPU heat sink off yesterday cleaned it and applied new thermal paste and my gpu runs no higher that 65 under heavy load if air flow was restricted it would go up way past that. Everything is stable in game no drops in fps or anything until the shut down. I have a feeling its the PSU failing and it can't supply enough power to card under load causing shut down, was just some cheap 20 quid one off ebay. Will buy corsair next time