Usually when there is a lot of harddrive thrashing my mouse movement gets glitchy as heck and jumpy. ie. when Transmission is checking a file or something. I am using Zephs 10.5.2 v1 install and the new speedstep 9.2.0 kernel.

AMD Opteron 165 (Dual Core)
DFI Ultra-D nForce4 Ultra
G.Skill 2gb RAM
eVGA Geforce 6800GS (QE/CI)
Buffalo WiFi (Broadcom chipset)
WD 120gb SATA (Leopard)
WD 250gb SATA (Time Machine)
WD 250gb SATA (Windows XP)
WD 500gb SATA (Files)