I know I've posted this as a reply in a few places, but maybe just sticking it in it's own thread will help out more people. This is a note for those who have no option to fix the problem but a new graphics card, who can't afford one right now (like me). These are the current settings I am running at, and I seem to be doing okay:
Disk cache size set to maximum.
Graphics:
-Draw distance 64
-run in a window
Detail:
-Normal rendering, turn off ALL the bells and whistles as far as lighting and such goes. I seem to still be able to have mesh details at default settings.
-terrain detail low
-no avatar vertex (dunno what difference it makes as I don't have it as an option lol)
Adv. Graphics:
-Graphics card memory set to 16MB. Your textures will suck majorly, but you lag less it seems.
-Max particle count: 0
-Outfit composite limit: 0
-fog distance ratio: 4.0 (I can't ever remember if you put that up or down to reduce lag though... I just tend to go to debug and turn off fog and clouds, though I haven't done that yet and am running okay)
Audio:
-No streaming is turned on.
Please note, the graphics card set at 16 seems to have made the biggest difference. My card says its memory is 128, but setting to 16 will sacrifice a bit of image quality for the ability to stay logged in without massive lag. If you see blurry textures and they drive you nuts, zooming in on them usually forces them to render. After several days of not being able to stay logged in for more than 5-10 minutes, I stayed on with these settings yesterday for a few hours before choosing to log off for the night, and managing to shut SL off without crashing. It made a HUGE difference.
It's not an ideal solution given the quality sacrifice, but if you can't get a new card, it's probably the best option until you can that I've found.
If it stops working for me, sheer stubbornness dictates I'll find a new solution and post it too. lol