Good idea. Look at the chips. You want to see something with an 8 or less. Usually the last digit on the chip will be something like "-8" or "-7" or "7ns" etc. This would reflect the speed of the memory chip in nanoseconds. You can easily look up the part number you see using a semiconductor cross-reference guide. This will tell you if the chips are compatible with the bus speed you want to run them on. If the DIMMs you have are 10nanosecond, they probably are not PC133. You want 7 or 8 ns speed. SisoftSANDRA will tell you info about the DIMMs that are installed on your motherboard. Click on "mainboard info" and it will return the name of the manufacturer and hopefully even the speed of the DIMMs. Don't freak out if it says your PC133 is PC100, its apparently a common problem with SANDRA. It will usually give you the DIMM part number and manufacturer so its easy to find out more.
P4 firstname.lastname@example.org dual R134A phase change chillers with 600watt thermoelectric array. Capable of -70F
Nixie tube numeric display control panel and pneumatic motherboard tray.