High CPU usage by compiz when idle in 12.10

On a new installation of 12.10 it shows compiz using all of one of my CPU cores when idle.

top - 07:08:49 up 1:44, 2 users, load average: 1.58, 1.35, 1.35
Tasks: 171 total, 1 running, 170 sleeping, 0 stopped, 0 zombie
%Cpu(s): 57.6 us, 5.2 sy, 0.0 ni, 37.2 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 4049836 total, 1705540 used, 2344296 free, 88124 buffers
KiB Swap: 4193276 total, 0 used, 4193276 free, 625128 cached

  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
 1861 stuart 20 0 1566m 294m 35m S 107.0 7.4 95:04.00 compiz
 1026 root 20 0 169m 24m 7640 S 8.3 0.6 7:18.64 Xorg
 1969 stuart 20 0 533m 24m 11m S 2.0 0.6 2:25.06 unity-panel-ser
 1971 stuart 20 0 638m 8696 4360 S 1.7 0.2 1:44.57 hud-service
 2381 stuart 20 0 554m 55m 27m S 1.7 1.4 1:57.53 plugin-containe
 1889 stuart 20 0 420m 12m 8820 S 1.0 0.3 0:57.68 indicator-multi
 3124 stuart 20 0 525m 18m 11m S 1.0 0.5 0:07.08 gnome-terminal
 3546 root 20 0 0 0 0 S 1.0 0.0 0:02.35 kworker/0:2
 1997 stuart 20 0 617m 5592 3928 S 0.7 0.1 0:39.43 indicator-appli
 2106 stuart 20 0 1016m 257m 37m S 0.7 6.5 3:43.31 firefox
...

CPU is a AMD Athlon(tm) 64 X2 Dual Core Processor 5600+ stepping 03 with 4GB of RAM.

There were no high CPU usage issues with this system running 10.04.

As requested for a similar report against 12.04 (209442) here is the output of sudo lshw -C display; lsb_release -a; uname -a; dpkg -l | grep nvidia

  *-display
       description: VGA compatible controller
       product: G72 [GeForce 7300 SE/7200 GS]
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:02:00.0
       version: a1
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
       configuration: driver=nouveau latency=0
       resources: irq:16 memory:f8000000-f8ffffff memory:e0000000-efffffff memory:f9000000-f9ffffff memory:fa000000-fa01ffff
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 12.10
Release: 12.10
Codename: quantal
Linux shelly 3.5.0-17-generic #28-Ubuntu SMP Tue Oct 9 19:31:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

As suggested in that issue I tried switching to ppa:ubuntu-x-swat/x-updates, but got messages indicating that there are no updates available for quantal.

Any suggestions for how to get the CPU usage down to a more reasonable level?