My Lan connection started going bad. Results on speedtest.net used to be 6-8 Mb/s downloading, 0.9 Mb/s upload with the link speed set to autodetect (100 Mbps). Currently the figures are about 0.16 - 1 Mb/s download, 0.9 Mb/s upload (i.e. upload speed > download speed). This is when I get a response - sometimes nothing happens. When I set the link speed to 10 Mbps, the download speed is 1.8-2.5 Mb/s, upload 0.07 Mb/s. The results with link speed set to 100 Mbps are the same as autodetect.
I am using the latest driver, on XP SP3. The connection and hardware tests all pass. I connected a laptop to the same cable, and this runs at normal speeds.