UBB.threads PHP Forum Software Community Forums UBB.threads Version 7/8 Support Board all of a sudden slow

Hi all. Our UBB board has, just in the last few days, started running very slow for all our members. The only change I've done this week is add an RSS feed for one forum with a 5 minute cache (Just changed that to 30 minutes). Still slow.

Would going to CP/Database Tools/Information and optimizing all the tables on that list help? Or might there be another possible candidate for the speed decline?

Thanks very much,
tee