This is what happened today when my iMac (July 2010) with 8 GB of RAM running Mac OS X 10.7.5 woke up, and Firefox 16.0.2 had about twenty pages open. Activity Monitor showed Firefox using a bit over 100% of the CPU:


Code:

6349752        0 drwxr-xr-x  40 root  wheel        1360 Oct 29 08:35 .
 6340724        0 drwxr-xr-x  30 root  wheel        1020 Jul 24  2011 ..
 6623341 16777216 -rw------T   1 root  wheel  8589934592 Feb  3  2012 sleepimage
24254572   131072 -rw-------   1 root  wheel    67108864 Oct 25 04:14 swapfile0
24254815   131072 -rw-------   1 root  wheel    67108864 Oct 29 08:38 swapfile1
25128048  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile10
25129379  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile11
25131085  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile12
25133074  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile13
25134916  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile14
25136487  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile15
25137949  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile16
25139705  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile17
25141499  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile18
25143137  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile19
24254817   262144 -rw-------   1 root  wheel   134217728 Oct 29 08:39 swapfile2
25144852  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile20
25146545  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile21
25148110  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile22
25149775  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile23
25151530  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile24
25153340  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile25
25154961  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile26
25156625  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile27
25158467  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile28
25160222  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile29
24494496   524288 -rw-------   1 root  wheel   268435456 Oct 29 08:39 swapfile3
25161964  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile30
25163580  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile31
25165264  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile32
25166930  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile33
25168766  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile34
25170544  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile35
25171685  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile36
24999858  1048576 -rw-------   1 root  wheel   536870912 Oct 29 08:39 swapfile4
25019401  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile5
25087182  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile6
25088637  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile7
25089967  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile8
25126739  2097152 -rw-------   1 root  wheel  1073741824 Oct 29 08:39 swapfile9

MicroMat Inc
Makers of TechTool