after our recent migration to much faster hardware and then upgrading out outdated 5.0.26 to 7.1.2 and moved to RHEL 5, all of my users even ones with faster machines are having terrible stuttering composing messages in IE 8, ive disabled the saving of drafts while composing which makes the problem slightly better. but today users just typing as fast as they normally do produce messages such as:

"o is this going o be ometig that we might etfixed? Do you thnk it sbecause of the new Zimbra? hnks- I know you all are bsy bu ths is gettig anoying nd really slowing m down!"

the pauses are eating keystrokes, the problem doesn't appear to be reproducible in firefox or chrome.

any ideas on how to fix this would be appreciated.