Advice on mixing RAM types to avoid crashes

For months, Fred Connors was plagued by unexplained crashes with his Power Tower Pro G3. At one point, he contacted Newer Technology Technical Support for advice. They wrote:

Check to see if your memory has the proper buffering and dampering chips. When running at faster speeds, it is important that your machine have the correct type of RAM installed. To check for this, look for the number printed on the middle chip on the memory module:

16244 indicates that it is buffered but not dampered and you do not want to use it in your machine.

162244 indicates that you have buffered and dampered RAM that is designed to work with faster CPUs.

When Fred checked, he found that he had some of both types of RAM installed. Removing the 16244 type eliminated all the problems he was having. However, he had difficulty finding a company that sold the desired 162244 chips. As a result, he did some experimenting and found that, as long as his Power Tower only used one type of chip, no crashes occurred. It did not matter which type it was. It was only when he mixed the two different types that the crashes returned.

This is consistent with more general advice that mixing RAM types (such as 60ns and 70ns RAM) in the same machine is not recommended.

[I confess to knowing very little about this buffered/dampered RAM difference, but I pass along the information in case it proves helpful to others.]

Update Stephen Trujillo (of MacGurus) similarly notes that the Power Tower cannot use 5v EDO RAM and must use FPM RAM (which is increasingly hard to find and looks almost the same as the 5v EDO). Apple Power Macs can typically accept either.