I've had a number of complaints lately from members saying that the site is running really slow.  When pressing for more information, it appears that the main complaint is when they are posting.  Once you click on the submit button, it can take quite a long time to post.  I suspect that it is related to the size of the activeforums_content table in the database.  It currently has 265k entries and is 450mb. 

Has anyone else seen this and what steps have you taken to resolve it?

Posting performance is usually related to sending email. Do you have the mail queue enabled?

Yes, the mail queue is enabled.

I've always had posting performance issues. It takes a few seconds to actually post after a user hits submit. You have to sit there for a while for the server to respond.

I also have the mail queue enabled.

Is there any performance work arounds that you can recommend?

Did you just recently enable Vanity URLs?

I don't use vanity URLs.