http://www.overclock.net/t/1133897/windows-7-ssd-tweaking-guide/0_100
For Firefox cache there is a way to store the cache in memory. This is what I do not only for speed, but for privacy.
Type in the address bar about:config
Find the keys:
browser.cache.disk.capacity. Change to 0
browser.cache.disk.enable. Change to false
Create a new integer value called: browser.cache.memory.capacity. Set the value to 51200. That's 50 MBs
Create a new boolean value called: browser.cache.memory.enable. And set it to true.
If this is a laptop you can move the temp directory to a RAM drive. I use Sofperfect's RAM drive. It will craet a folder name of your choice, I called mine temp. Set the RAM disk size to 200 MBs so you don't run into any problems.
http://www.softperfect.com/products/ramdisk/
I would also go into Internet settings in the control panel and move the temp directory to the RAM drive. I don't use IE, but it still creates files.