Bizarre Transmission-induced network bug, driver crapping out maybe?

[Chris Neary]

I've had a crazy bug manifest itself for the last couple of versions
of Ubuntu, and it's always drove me insane because it makes no sense.

The facts:

* My machine dual-boots Windows and Ubuntu.
* Windows can download BitTorrent for hours, seeding until whenever
(uTorrent, Vuze)
* Ubuntu seems to download fine for a while, until which point all
network connectivity is lost. (Transmission)

By 'a while', it seems I mean only a few moments, since it happened
again as I was writing this. I'd ony just re-started the machine and
started Transmission again.
Rebooting is the only way to get the network interface to be
re-enabled, I've found. Not too sure about ifupdown commands, but
maybe that would fix it too.

The tell-tale signs that this has happened are there: All my torrents
are displaying 'Remaining time unknown, idle', and if I ping
192.168.0.1 (my local router), I get destination host unreachable.

The router is alive, as is my cable modem (moot, as it's not the point
of failure here).

I've pondered the likelihood that Transmission is somehow overloading
eth0 (wired), and is causing its driver to panic.

Any thoughts?

I really don't wish to boot in to Windows just to download BitTorrent.
Games, yes. MS Office, perhaps. Trivial, everyday stuff? No!

Motherboard is onboard, SIS190. This never happened with my Acer
Aspire One via wireless, so I'm assuming its the driver/eth/board.