The problem with the default Linksys router firmware is that it doesn't close down connections quickly. Torrents work by throwing out masses of connections in the hope that something will stick. This eventually gums up the router's memory, and eventually grind to a halt.
The answer is in use of third party firmware, but also in configuration of the firmware, and having sensible settings on your PC's software.
The DD-WRT firmware, v23 or later, can be downloaded from
here:
You then need to change some settings:
* Enter the following values at 'Web-Admin -> Administration -> Management -> IP Filter Settings'
* Maximum Ports: 4096
* TCP Timeout (s): 300 (decrease if you have many TCP connections)
* UDP Timeout (s): 300 (decrease if you have many UDP connections)
* Save Settings and then Reboot Router
In your torrent clients try limiting the number of active torrents and also the number of connections. On 4 meg I've found something like 100 connections, 4 torrents and 20KB/s upload is about right. The upload doesn't want to be much more than 80% of your maximum capability.
Once I've made those adjustments, I've found my Linksys WRT54GS has been running with torrents nice and happily.