It was not good, and having recently doubled my RAM I had memory to spare.
I downloaded Gavotte RamDisk (instructions page here) and set up a 512MB RAM disk.
I use Firefox Portable (link) and, after emptying the cache and reducing the cache limit to 300MB, copied it over to the RAM disk.
- App startup time faster by 40%
- App shutdown time faster by 60%
- Firefox RAM use reduced by 30%
- CPU load reduced by 50%
- Video no longer lagging
- Browsing snappier
- HDD not constantly spinning
- Laptop fan spinning much slower
There are three disadvantages to this setup:
- Cache is lost on reboot
- Application prefs/bookmarks are lost on reboot
- RAM disk must be set up after reboot
The third problem is what it is, though it can take as little as ten seconds plus copying the application folder over.
A probable further benefit of this setup is battery life, which I haven't tested yet.