Wondering what you can do with the multiple gigabytes of system memory that are otherwise going to waste? If you are a heavy Firefox user you might want to consider using your excess RAM as the cache location for your browsing session; rather than the order of magnitude slower hard disk – the more traditional configuration. Moving your cache storage to system memory should result in a noticeably faster loading of web sites, especially the heavier AJAX sites like Gmail.

Many Firefox tweaks involve digging into about:config from the Firefox address bar and this one is no different.

The preferences we wish to tweak begin with browser.cache which can be accessed rather quickly by utilizing the Filter box.

First, disable the disk-based browser cache by toggling browser.cache.disk.enable to false.

Then, enable the memory-based browser cache by toggling browser.cache.memory.enable to true.

Create a new preference named browser.cache.memory.capacity with right-click->New->Integer.

For the capacity the value stored is in KB so for a value of 150 MB you’ll want to use 150000. This value is solely defined by the amount of system memory you wish to dedicate to the memory cache. If you have gigabytes of system memory to spare you may set this to something like 500000 for 500 MB of caching.

Your browser.cache settings should now resemble something like the picture below.

Once you are satisfied, restart Firefox to apply the changes. Recall that since the cache is stored entirely in system memory, starting and stopping Firefox for every browsing session will clear out the cache, potentially undermining the speed-up you are trying to obtain.