Intel 4965AGN wlan slowdowns in XP

[akeskira]

I have an X61 with Intel AGN wireless in an XP setup. All drivers and patches should be the latest. The wlan driver version is 11.1.1.16.

I have no problem using the net, except when I start heavy downloads such as torrents. The downloads themselves proceed ok, but they slow down the whole network stack of the XP. This can happen even with download speeds as low as 200-400 kBps. My old 2200BG based setup had no problems handling downloads up to 1.2 MBps.

In other words, when I am downloading something, other net dependent programs such as web browsers become almost unusable. Closing the download will fix the problem after a few minutes.

Initially I thought this was a wlan router issue, but the other computers in the same wlan can access the net without any problems or slowdowns.

Do you have any clue how to fix this? I've encountered similar symptoms when a wlan access point was running out of ports. That was easily fixed by increasing the amount of ports in TCP settings.