Starting a game disconnects the internet

[u2sunstuff]

I have to admit I am in a bit of a jam , the sticky kind. Here's the deal , fresh windows 7 install , updated , tried the motherboard cd NIC card drivers, tried the ones on the motherboard manufacturers site , even tried the latest realtek ones. Every other driver is up to date , the problem is really annoying, whenever a game is started , my internet connection disconnects, sometimes after 2-6 minutes of playing online (starcraft 2 Beta.. never in the menu), in other games as this offline singleplayer (singularity) got it after 10 miuntes .
No error message just network cable unplugged , the router is not the problem here as I tried bypassing it and logging straight to my PPOE connection , same problem.
Reinstalled windows and tried again , no luck. Updated bios to the latest , problem persists. Using a separate card in my PCI slot doesn't make the problem go away. The other computers in my house do not do this , but this should be my gaming rig.(in progress)

The system :
Windows 7 Enterprise 64 Bit
AMD Phenom II 955 BE @ stock
4 GB DD3 (don't think it matters)
AsRock 890GX Extreme 3
NIC - Realtek PCIe GBE Family Controller or as ASrock site said Realtek RTL8111E


I should mention that browsing or downloading files of any size or shape does not cause this .
Any help would be really appreciated I'm out of ideas.

 

[u2sunstuff]

If anyone is interested I actually found the cause of the problem , it's the onboard video of the AsRock 890GX Extreme 3, the 4290, has a built in bios overclock and is really stable up to 1 GHz(the max aviable option), but seems that even if it's at 800 MHz instead of the stock 700 the network disconnects the moment you start a game. I used the onboard video until my order came , and as soon as the crossfire 5850 went in the problem was fixed.