I get you and cmaffia are on the same system. Was not my point.
I'll be clear: I don't know why you and Charles experience this behaviour, and I'm willing to look into it, this is why I'm still replying here although the thread has turned into arguing.
Why could it be a local problem? Because this does not happen to several thousands of users. What triggers the decrease in performance could be anywhere, including OS updates (besides IE, also .NET was updated), this is why we need to check.
So, I'm not saying for you the root of the problem is not 7.5.30 - but that if there are issues, we need to spot them, so that the final releases can be more solid for as many users as possible. Just that.
Have a nice week-end.