I've had this problem for almost a year and I tried what you said... FINALLY my problem went away. I was crashing a dozen times a day and I only crashed once since and I believe it was for other reasons other the the texture cache.
Thanks for your post!
I just got a new imac with a ATI Radeon 6970M 2GB graphics card. The card is not listed on the system requirements list, is that why I keep crashing. Crashes about 5 times an evening.