System slow after suspend and resume

[Alan Pater]

GUI gets very slow after suspend/resume cycle.

Menus lag significantly, windows are slow to move around, even web pages load slowly.
This happens under different GUIs. Both Unity and Lubuntu show the same issue.

Top does not show any misbehaving applications, nothing is using a lot of CPU.
Free indicates that there is plenty of free ram, the system is not swapping to disk.

To try and quantify the problem, I ran gtkperf & hdparm before and after.

Before hdparm -T returns 900 MB/sec, after: 143.51 MB/sec
 (hdparm -t does not change)

gtkperf -a gives a total time of 10 seconds before, and 80 seconds after.

To clear up the problem and return the system to normal performance, I need to shutdown, count to 20, and restart. A simple reboot does not clear the problem.

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: pm-utils 1.4.1-9git1ubuntu0.1 [modified: usr/lib/pm-utils/pm-functions]
ProcVersionSignature: Ubuntu 3.8.0-27.40-generic 3.8.13.4
Uname: Linux 3.8.0-27-generic i686
ApportVersion: 2.9.2-0ubuntu8.2
Architecture: i386
Date: Fri Aug 2 09:12:51 2013
InstallationDate: Installed on 2012-08-17 (349 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha i386 (20120724.2)
MarkForUpload: True
PackageArchitecture: all
SourcePackage: pm-utils
UpgradeStatus: Upgraded to raring on 2013-07-18 (14 days ago)