This might help if you got lot ram
Just tried it on my laptop with 2gig I do believe it help things
Putting the Firefox network cache into the RAM
3.1. By moving the Firefox network cache from your hard disk to the RAM, you diminish the amount of disk writes. This'll probably make your Firefox noticeably faster as well. The price you pay is small: it'll only "cost" you 512 MB of your RAM.
Note: don't do this when your computer has only 2 GB of RAM or less! Because with very little RAM, even 512 MB can't be missed.
Proceed like this:
a. Type in the URL bar of Firefox:
about:config
Press Enter.
b. Now you're being presented with a warning. Ignore it and click on the button "I accept the risk!".
c. Copy/paste the following into the filter bar (search bar):
browser.cache.disk.enable
Toggle its value to false by double-clicking it: this will disable "cache to disk" entirely.
d. (expired)
e. Then you're going to determine how much memory can be used as RAM cache. Copy/paste this into the filter bar (search bar):
browser.cache.memory.capacity
The current integer value will probably be -1, which automates the maximum size of the RAM cache dependent on the available amount of RAM. So far so good, but this automation usually creates a cache that's far too small....
So set it to 524288 (KB, which equals a maximum of 512 MB). That's usually enough for all amounts of RAM. But if you have RAM to spare, I recommend 1048576, which equals a maximum of 1 GB.
f. Close Firefox and launch it again. Then check it like this:
Type in the URL bar:
about:cache
Press Enter.
By the way: you'll then also see a mention of an "appcache" which might still be present on the disk, but there's absolutely no need to move that (much less frequently used) cache to the RAM as well.
Note: This is a user preference. Repeat this hack in each user account.
