i have the same issue, crashes every 10 Min's sometimes after 2 Min's,
i am also on windows 8 64 bit OS 8GB RAM (Laptop)
iv try'ed everything mentioned in other posts e.g. changing the ram allocated to the launcher, deleting the openGL.dll file clearing the cache, removing Java completely and re-Downloading java 7 64 bit, etc
anyone have a solution? i thought it was because im on windows 8 but loads of other OS's are having the same issue...