I need to run some sort of performance benchmark to measure how slow my MacBook Pro is (and why)—a 15" MacBook Pro (late 2008) with a  2.4 GHz Intel Core 2 Duo processor, 4 GB of DDR3 memory, and running Mac OS X Lion 10.7.4 very, *very* slowly. Most of the tasks I perform (e.g. deleting a file or folder, typing letters, switching desktops, etc) take more than an unacceptable 10-30s response time. I also have a second, 22" monitor.

Is there any way to measure a MacBook Pro's response time? Is there any free software I could use to run a performance benchmark and understand why it is so slow?