slow download speed with GA-880G-UD3H REV 1.4 MOTHERBOARD

[pylotttt]

Gigabyte GA-880G-UD3H REV 1.4 MOTHERBOARD
WINDOWS 7 X64
NVIDIA GTX 460
AMD X6 1055T
Gskill 8GB RAM

I play online games at steampowered.com. When downloading maps for farcry 2 the desktop is very slow, often timing out(5-10 minutes). My laptop downloads immediately taking about 1 second to download the maps. I have compared settings and all look the same except the connection setting on the desktop shows 100mhz while the laptop shows 1ghz. The adapter setting for speed and duplex has been tried both at 1.0gbps and auto negotiate but no change.
Both have the same operating system and network drivers.
I tried downloading and re-installing the network drivers, no change.
I have swapped the same cable from the router at each computer and the problem does not change.
I have tried a D-Link 1ghz network card, no change.
I have tried turning off the virus checker software, no change.
Windows firewall is off.
I have removed and re-installed steam, no change.

Why am I having this problem?
What else can I check?
Has anybody else had this problem?

[Dark Mantis]

Well it is a funny one and you have done most of the usual things to try and clear it. Try clearing the DNS on your main machine.

Open command prompt by typing cmd in the run box

next type "ipconfig /flushdns" into the DOS prompt and enter.

If that still doesn't work I would suggest a fresh installation of Windows.