Mail.app performance after upgrade to Lion I am having some big issues with Mail.app after upgrade to Lion. Performance is horrible.

When i open a message, cpu usage grows up to 150% See monitor activity screenshot

I already tried to repair permissions and remove all accounts to recreate it but it didn't make any difference.

I'm using 2 accounts with imap. The total messages on inbox is 12.000. Before upgrade, it was running fine.

Anyone experiencing this? Any ideas of what should i do?
If you open the Mail's Activity window (keyboard shortcut: Command+0), what does it show that justifies the 150% CPU figure?