Most the site now runs from memory and doesn't get anywhere near a database with slow, moving parts (disks). There are still a few sections that use the database, but we're working on getting rid of those as well.
If you encounter problems with the new code, please report them to the support area and we'll look into them. Affected code includes friends pages and reply counts.
This isn't the end of our performance work, though. We have a nice list of more stuff to work on, and it's all fun/easy compared to this latest project. We'll keep you updated.