Here's the problem - RAM rarely has any markings on it that indicate what type or speed it is. If it's generic, you're probably out of luck in terms of finding out. If it's name-brand RAM, you can call up the manufacturer and give them the serial number, and they should be able to tell you what type it is. However, since it's more than a year old, I'm guessing it's mucho slower than 100Mhz, considering 100 mhz wasn't standard for CPUs even six months ago.