[Nouveau] GeForce 5500 crashes driver

[Flo]

Hi all,

I have a 7 year old computer which is working fine so far and sufficient
fast for my 'office' needs. I am running Debian testing. I bought a new
monitor (HD) and a video card:

256 MB GeForce FX5500, Inno3D, AGP 8x/4x

Working fine, unfortunately it produces a crash:

.) Sometimes after 30 min, sometimes after a day
.) Can happen anytime, even when screen saver is on. Happens more
frequently if 'complicated' websites at browser windows are opened.
.) Mouse is still moving but everything else on the display is frozen.
.) I cannot switch to a console but I can login via network (i.e. to
reboot).

I conclude that the crashes are due to the combination of video card and
driver. So, the card is buggy or the driver is buggy.

I hope you can help me answering the following questions:
.) Is it reasonable to track down the error? (Maybe it would make sense
for driver improvement?). What should I start with?
.) How are the chances that the problem will go away if I buy a similar
(maybe also GeForce 5500) video card from another manufacturer.

I really appreciate your help.

Thanks in advance.

Flo.