Endless Hard-Drive Thrashing

I am running a fairly decent computer.

Windows Vista 32bit - SP2
4 gigs of ram
Nvidia 8800 GT 512 ram
Intel Duo 3 Ghz
Two hard-drive raid 0 for 640 gigs of space

Not sure whats with second life - but if I load into a new area or a sim I've been to several times or event at random times, SL really starts thrashing my hard-drives and I've tried everything reducing graphic settings, Defraging all of it and still doesn't seem to help.

Anyone have any solutions?

What is your cache size set to? with that much ram I can't see you using the page file much at all unless other programs are running and filling your memory up. if you're running out of memory and using the page file then all those small texture files will thrash the drives in a RAID set up even harder. The only other time I've seen this behavior is when I used a thumb drive in Ready Boost mode. Thrashed it hard for some reason.