There have been lots of recent posts about the crappy performance of LogMeIn on Macs. I had stopped using LogMeIn all together, till I found the solution (for me at least) given by PaulJi back in March in the thread "OS X browser plugin version 1.00.660 causes high CPU usage"
Revert from current plugin 1.00.660 to the old plugin v 1.00.562 by finding the old installer package (if you are lucky enough to have kept it) over the top of your current update
Spotlight search for npRACtrl.dmg on your cpu. Run it, overwrite your new version with the old, and instantly your back to rapid performance (I'm using Safari, and OSX 10.6.8 both ends)
I found the npRACtrl.dmg file on my computer but if I inspect the DMG file and look at the plist.info file it has the version string "1.0.660 Copyright (c) 2003-2012 LogMeIn, Inc." So it seems to be version 1.0.660. Does anyone else show this? Installing it also did not fix the problem.
To see the version information: Double-Click on the DMG file to mount it. Open up the LogMeIn Client Installer.pkg file by right clicking and "Show package contents". Open the folder "Contents" then Double-Click info.plist.
I chatted with LMI Help and they gave me this link to a previous version of LMI. This upgrade-downgrade did drop my CPU usage from 100% to 15%, and although I am still experiencing bad lag, it's hard to say whether that is LMI's fault or the fault of my connection across the internet.