Comment 23 for bug 74179

As mentioned in comment #12 this is primarily triggered by the memory not all being below the 4GB physical boundary. The correct solution is to use a PAE enabled kernel. This was discussed at Karmic UDS and the flavours updated such that there is a generic and generic-pae kernel. These should be selected automatically based on the installed memory size. But if you are running i386 and not seeing all your RAM you should install linux-generic-pae and see if that fixes the issue. If it does not then you should file a new bug.

Closing this Fix Released as the original reporters issue was fixed in Karmic by that kernel.