Just installed 11.10, but it's not detecting all 8GB of RAM. System Info says there are 3.9GB. Bios doesn't have a problem recognizing all 8.
free -m
results in:
total used free shared buffers cached
Mem: 3957 1478 2479 0 22 687
-/+ buffers/cache: 768 3189
Swap: 4089 0 4089
cat /proc/meminfo
?uname -a