Comment 4 for bug 1275193

I just saw this behaviour as well. Here's the output of top I managed to capture with mem and cpu usage before it ground my system to a halt:

top - 12:03:51 up 14 days, 1:54, 4 users, load average: 5.22, 5.50, 3.16
Tasks: 297 total, 4 running, 291 sleeping, 0 stopped, 2 zombie
%Cpu(s): 2.9 us, 0.9 sy, 0.1 ni, 96.0 id, 0.1 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 16465108 total, 16297996 used, 167112 free, 0 buffers
KiB Swap: 11811176 total, 697772 used, 11113404 free, 70728 cached

  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
17893 root 20 0 16.2g 11g 904 R 96.7 74.8 8:51.44 udisks-daemon
17912 root 20 0 30060 1128 812 R 96.7 0.0 8:53.24 udisks-helper-m
 1769 root 20 0 541m 302m 37m S 38.7 1.9 131:04.29 Xorg
 3524 graeme 20 0 2084m 367m 33m S 6.4 2.3 130:14.14 compiz
 5264 graeme 20 0 4107m 2.0g 13m S 6.4 12.7 1252:50 firefox
    1 root 20 0 27624 2308 636 S 0.0 0.0 0:01.67 init
    2 root 20 0 0 0 0 S 0.0 0.0 0:00.12 kthreadd