Snow, Streaks then Crash

I'm a newby and apologize if I'm covering old territory. I've read other threads, but can't find anything that matches my experience.

After I log in, my images become progressively worse over a period of anything up to an hour (but mostly 5-10 mins) before I crash. First I notice what I'd describe as snow (small pixels of white), then streaks will flash from avatars and other objects, then diagonal streaks will cross my screen and I'll eventually crash. Some SL locations seem less affected than others.

I'm running a 3.4 GHz P4 with 2 GB of memory, an ATI Radeon X600 video card (latest drivers), under XP Pro. My cable is blazing at 6.6 Mb/sec. I've tried to scale back the graphics settings, but see no difference.

Is it my graphics card? I'd hate to lay out $$ for an nVidia 7900 if it won't help. According to the specs, the X600 is not that far off (perhaps I'm not interpreting them right). Has the card just gone bad? I've had ATI error messages saying it had to reset my card after some crashes. The card works fine outside of SL.

Any advice would be most welcome!

That sounds like an over heating problem, I had this with another game and found it was actually my fans not cooling my stuff down enough.

I took the side off my modem and let air get in and tried it, and it seemed to help, so i bought a new fan and things have worked fine.

I have about the same type of running equipment as you and it works fine. hope this helps, but please dont quote me that this is the problem, it just sounds like something that happened to me.

But it definately sounds like the graphics card is over heating.

Thanks for the suggestion. I'll keep an eye on the heating issue although I have a virtual wind-tunnel through that box.

Since I was in a rush to fix this, I went out and bought a nVidia GeForce 7900 GS. Just installed it and the results are like day and night.

"then streaks will flash from avatars and other objects, then diagonal streaks will cross my screen"

That sounds excactly like my old ati9800pro when i used it on secondlife , ram was faulty,used it for years then that happend, but oh well old card so sendt it back on warranty.