I think it is pointless to base browser choices based on performances on other people's machines. Each browser is optimize for a specific operating environment dependent on a multitude of factors, such as: operating system, system RAM, processor architecture, etc...

To find out the best browser for your machine, you need to run the tests yourselves on that machine. A browser that achieves optimal performance on another person's machine may be horrible for your own.

Some browsers are efficient at conserving system resources while others are optimized to be the fastest possible on high-powered machines.