Look at this photo:
What you can see here? Some 168 pin DIMM? The first 3 looks like devices from same family… but they are very different. From left to right:
1. It is ROM! “Phaser 850 Ver 1.1 Roman Fonts. (c)2000 Xerox Corp. bla bla…”
2. It is 5V, buffered DIMM. Used is old Apple computer, also in some other exotic
3. It is PC100 3.3V DIMM. The one you use in PC world. (old pc…)
4. It is DSIMM used in Sun SPARCstation 10.
The first 3 differs only by position of the notches. The notches indicated voltage: 5V, 3.3V and reserved and type: unbuffered, buffered, reserved…