High idle load on 64bit Ubuntu 12.04 with 3.2.0-24-generic kernel

Since the update to 3.2.0-24-generic kernel and despite >90% of idle CPU the load remains relatively high. On 3.2.0-17 it used to be barely above 0, now it rarely drops below 1. Powertop also reports high power usage by the CPU (~8W). The processor is 2.4GHz Intel i5-2430M and going back to 3.2.0-17-generic solves these problems.

$ top

top - 23:27:42 up 26 min, 3 users, load average: 1.66, 1.80, 1.46
Tasks: 216 total, 1 running, 214 sleeping, 0 stopped, 1 zombie
Cpu(s): 0.2%us, 0.3%sy, 0.0%ni, 99.5%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 8082692k total, 2235412k used, 5847280k free, 159640k buffers
Swap: 8294396k total, 0k used, 8294396k free, 984832k cached

  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
 3764 rmo 20 0 1075m 260m 38m S 1 3.3 1:39.84 firefox
 4514 rmo 20 0 17452 1512 1072 R 1 0.0 0:00.12 top
 1772 root 20 0 236m 6628 5236 S 0 0.1 0:00.47 NetworkManager
 2013 root 20 0 154m 23m 8008 S 0 0.3 1:09.09 Xorg
 3294 rmo 20 0 1190m 74m 30m S 0 0.9 1:28.46 compiz
 3501 rmo 20 0 575m 20m 11m S 0 0.3 0:10.38 gnome-terminal
    1 root 20 0 24544 2516 1380 S 0 0.0 0:01.22 init
    2 root 20 0 0 0 0 S 0 0.0 0:00.00 kthreadd
    3 root 20 0 0 0 0 S 0 0.0 0:00.20 ksoftirqd/0
    6 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/0
    8 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/1
   10 root 20 0 0 0 0 S 0 0.0 0:00.18 ksoftirqd/1
   13 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/2
   14 root 20 0 0 0 0 S 0 0.0 0:00.60 kworker/2:0
   15 root 20 0 0 0 0 S 0 0.0 0:00.09 ksoftirqd/2
   17 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/3
   19 root 20 0 0 0 0 S 0 0.0 0:00.06 ksoftirqd/3
   21 root 0 -20 0 0 0 S 0 0.0 0:00.00 cpuset
   22 root 0 -20 0 0 0 S 0 0.0 0:00.00 khelper
   23 root 20 0 0 0 0 S 0 0.0 0:00.00 kdevtmpfs
   24 root 0 -20 0 0 0 S 0 0.0 0:00.00 netns
   26 root 20 0 0 0 0 S 0 0.0 0:00.00 sync_supers
   27 root 20 0 0 0 0 S 0 0.0 0:00.00 bdi-default
   28 root 0 -20 0 0 0 S 0 0.0 0:00.00 kintegrityd
   29 root 0 -20 0 0 0 S 0 0.0 0:00.00 kblockd
   30 root 0 -20 0 0 0 S 0 0.0 0:00.00 ata_sff
   31 root 20 0 0 0 0 S 0 0.0 0:00.01 khubd
   32 root 0 -20 0 0 0 S 0 0.0 0:00.00 md
   34 root 20 0 0 0 0 S 0 0.0 0:00.00 khungtaskd
   35 root 20 0 0 0 0 S 0 0.0 0:00.00 kswapd0
   36 root 25 5 0 0 0 S 0 0.0 0:00.00 ksmd
   37 root 39 19 0 0 0 S 0 0.0 0:00.00 khugepaged

$ uname -a
Linux flax 3.2.0-24-generic #37-Ubuntu SMP Wed Apr 25 08:43:22 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

What other information should I include? How can I fix this problem?