Improving Load Times on High Traffic Sites
By Paul
07/28/05 (Edited 10/05/06)

Consider making toplists static as described at http://www.webmastersite.net/forums/thread/5827 . Also see the tips at http://www.webmastersite.net/forums/thread/5254

If you're desperate, or you're being attacked unjustifiably by spiders, you can use the load management at Admin -> Settings -> System to lock out spiders when the load gets too high (note that this depends on having a Unix-like server).