Luned: It was known for rubberbanding at times in 2006. Any items or skills that increase (or decrease!) your (or your enemies') movement speed will tend to increase rubberbanding. If you have turned the game speed up to Fast or Faster in the AE settings, that would probably also increase rubberbanding.

HappyUnicorn: I've played TQ+IT years before the Anniversary Edition and me and my friends always had this kind of problem, no matter the rig. I guess it is the fault of the game engine itself.

Splatsch: I've maybe found some possible fix, but I wasn't encountering the problem often enough to confirm it works :
"[...] set this setting in the options.txt file : forceSingleProcessorMode = false" (found here).
Here's the path for the file :
"C:\Users\XXXX\Documents\My Games\Titan Quest - Immortal Throne\Settings"

And another solution here (but more complicated)(so I haven't tested it, the problem wasn't occurring often for me).
A simplified version of this one is in the second post of the thread, here is a copy/paste of it :
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Simplified version, no RAM-Disk needed (for Windows 7, for other versions of Windows some details might differ):
1. You have to have administration rights on your machine, otherwise you can't do some of the necessary steps
2. Make sure Titan Quest is not running
3. Copy your savegame directory to another hard drive or partition (usually it's C:\Users\YourUserName\Documents\My Games\Titan Quest - Immortal Throne)
4. Delete the original savegame directory (not just the contents, the whole "Titan Quest - Immortal Throne" must be deleted)
5. Check the path to where you copied your savegame directory. I did it simple - straight to drive E: so path was E:\Titan Quest - Immortal Throne
6. Start a command line with admin rights (enter "cmd" into the searchfield of the startmenu an hit enter. Now you should have an open command line with admin in its title)
7. Navigate to the "My Games" directory where the savegames used to be, type: cd c:\users\YourUserName\documents\my games
8. Now the symlink must be created. The command for this is "mklink"
- more info on symlinks and the exact usage for mklink can be found at http://en.wikipedia.org/wiki/NTFS_symbolic_link
Use command mklink /D
- in my case it would look like this: mklink /D "Titan Quest - Immortal Throne" E:\"Titan Quest - Immortal Throne" press enter, you should get - Symbolic link created for

9. Now you can test with your explorer if it's working. Browse to C:\Users\YourUserName\Documents\My Games\Titan Quest - Immortal Throne and look if the contents are in there. If they are then you have completed all steps. Worked for me, might not work for you.
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I don't know at all if any of this works, but I hope this will help some :)