Those improvements for the Windows, Apple OS X and Linux versions of the software are achieved in several ways. One of the biggest performance enhancing additions in Firefox 7 (code named Aurora) is the introduction of MemShrink, which Mozilla hopes will change Firefox's reputation as a memory hog.

MemShrink can reduce Firefox 7's memory usage by anywhere from 20 to 50 percent, according to Mozilla, and improve performance in responsiveness, startup and page load times. You can download the .

With MemShrink, Firefox 7 memory usage will remain constant for long periods of time and closing many tabs will free up more memory. "This means that Firefox 7 is faster (sometimes drastically so) and less likely to crash, particularly if you have many websites open at once and/or keep Firefox running for a long time between restarts," Nicholas Nethercote, a Mozilla developer in Melbourne, Australia, explained in .

Better Garbage Collection

Another change aimed at boosting performance is better JavaScript garbage collection. It works more frequently now to free up memory faster and improve performance when many tabs are open at the same time.