BIG loss of internet speed on one computer

[Gustavus]

I have multiple computers, all running Windows XP with SP2, connected to the internet through a common DI-604 router. My ISP is Comcast and I have very good broadband cable service. Speakeasy and SpeedTest routinely measure download speeds of 10 Mbps or a bit better depending on the time of the day etc. I am a bit of a nut on the subject and routinely measure speeds with both software packages when I turn on machines. All machines are protected by NOD32 AV, Outpost Security suite firewall and regular scans with Trojan Remover.

The machine I regard as my main computer (3.2 GHz on an ABIT IC7G motherboard) suddenly dropped from 10 Mbps to around 1 Mbps. The other machines are still measuring around their normal bandwidth of 10 Mbps or a bit better. Rebooting or restoring to a previous state has no effect. Connecting the machine directly to the modem doesn't either. Virus and Trojan scans show no malware. Registry scrubs with several registry cleaner softwares also have no effect. The bottom line is that a machine which has been measuing 10 Mbps has suddenly dropped to 1/10th of that speed while none of the other machines have lost any bandwidth. Comcast has verified the modem is working properly -- which I already knew. No hardware changes have been made to the machine in question for over a year -- it is my main machine after all.

If anyone sees a possible explanation, I would appreciate you letting me know what it could be. The problem is clearly unique to this one machine since none of the others are affected, but I am at a loss as to what the problem could be.

Thanks.

 

[mpilchfamily]

Try reinstalling the networking drivers for your motherboard. If that doesn't help then the network connection on your motherboard may be going bad. In which case you'll just have to buy an NIC.

 

[MadAmos]

After removing and reinstalling the NIC drivers, I would try a new cable from the router to the computer also try disabling or even removing the firewall software and see if that brings your speed back.

 

[Gustavus]

Thanks for the replies. One of the first things I did was to connect the computer directly to the modem using a new ethernet cable. Had to open a new one to get the length required, but as I mentioned that didn't make any difference. The ethernet adapter is Realtek RTL 8139. I will reload the drivers tonight I have a box of five unopened D-Link DFE-530TX ethernet adapters in the lab, so it will be an easy matter to try one of those. If anything works I will post back here.

 

[Gustavus]

Problem solved. I replaced the ethernet card with a new DFE-530TX and reinstalled the drivers. Now logging over 10 Mbps in both Speakeasy and SpeedTest -- to Los Angeles and to Dallas. Sure glad to be back among the living. Felt like the old dial up days at 1 Mbps.