I just tested it in our environment and it works fine, as user and admin IE 10 has 32-bit processes. You must be looking over something and have the TabProcGrowth registry key set through either a group policy or in some other way.
Check the following registry values (logon with a user and check his registry settings while logged on):
or if that one doesn't exist it's using this one:
With the logged on user, close all his IE windows / processes and add it to his registry TabProcGrowth value 1. Then try again.
I'm sure you have that value set, you're the only one with a topic about this issue. If it was a common issue there would be more topics about it.