Yes, it's doing a basic RAM test. You can't do it on all Macs, but you can likely disable the startup memory test by holding down option + command (I think) when you double-click on the "memory" control panel. There will be a check box at the bottom of the control panel that lets you turn it off. Saves a lot of time on some machines (eyeing off my PowerMac 9600 with 1536MB!)

JB