ASUS GT640 compatibilty

[Tommyugn1982]

Hi,
I have recently rebuild my system with mainly new components, however I have come across an issue with the above graphics card.
When I was trying to install windows 7 on the system with the ASUS GT640 in the system I was constantly suffering from the computer randomly reboot looping. I had my suspicions that it was my PSU as this is what is second hand in the machine albeit its a 700w PSU.
I then installed my old gfx card into the system as process of elimination as to where the problem lay. My old GFX card is an GEforce 8800GTX. With this card in the system Windows 7 installed fine and was able to use the computer perfectly fine.
As the ASUS GT 640 is brand new I tried it again in the system now with windows installed. The computer booted up fine entered windows fine. Then after about 5 mins on the net the computer reboot looped again.
By now I am totally puzzled and am unable to use my new gfx card in my system. Im pretty stuck and am lumbered with what im not sure is a faulty card or a system that is impatible with it.
Currently unable to try try it in another system as well.

My system specs are :-
ASUS P6T Deluxe x58 Motherboard
Core i7 920 2.66 processor
6gb RAM
brand new 1TB HDD
700w PSU
GeForce 8800GTX (currently in system)

Any help or direction would be greatly appreciated.
I'm no computer whiz but I have built a few systems and this is annoying me terribly.

 

[haider95]

Monitor temperatures using GPU-Z and if the temps spike then you've got yourself a faulty GPU. Its not the PSU trust me.. If it can power a 8800GTX then it can surely power a GT640. You do realize that the 8800GTX is actually better than the GT640 despite being older? The only thing it lacks is Low power consumption and DirectX11

 

[JackNaylorPE]

Uninstall GFX card drivers before switching cards.

 

[Tommyugn1982]

Thankyou for your replies all help is much obliged! I have so far been unable to keep the system on long enough to both monitor the cards temperature or even install any gfx card drivers! When i did get into windows with this 640GT card I managed to change resolution then attempt to get onto nvidia website to download the drivers which was when it went on its reboot loop again
Is there any way I can monitor temperatures outside of windows as getting into windows seems a no go with card!
I swaying towards the fact I have a duff card at the moment but I'm not overly experienced in this field so thought I would explore every avenue and exhaust every option with some expert help off here!
Thanks again for the help.

 

[Tommyugn1982]

Bump

 

[haider95]

get into windows in safe mode. un-install all previous drivers and just install drivers from the cd that came with the graphics card