Comment 12 for bug 98783

Comment #11 is a good summary of the situation. Currently, none of the comments on this bug provide sufficient information to do troubleshooting. Memory usage problems tend to be very hard to debug, especially when they cannot be reproduced independently.

For people using the -nvidia driver, you're almost entirely out of luck - the binary proprietary -nvidia driver replaces pretty large swaths of the xserver's internals with its own code, so debugging issues with that driver are almost always futile. If the bug is sufficiently well reported, it could be forwarded to -nvidia, but so far not enough has been provided.