This is a paragraph from http://www.dans20thcenturyabandonwar...rsonal-ch.html
The Pavilion xt878 is my computer.
The truth about HP and the Pavilion xt878. In 2004, I decided to research this system's motherboard to find out what its upgrade limits were. I discovered the motherboard is an ASUS A7M266-M and has two front side bus speeds -- 200MHz and 266MHz. HP released this system with a 200MHz FSB 1.3GHz AMD Athlon "Thunderbird" CPU. There is also a 1.3GHz Athlon with a 266MHz FSB but HP elected not to use it. HP also released this system with DDR PC1600 (200MHz) RAM, though it is capable of running PC2100 (266MHz) RAM. A jumper on the motherboard sets the FSB speed at either 200MHz or 266MHz.
"I was slightly miffed when I learned I had used this computer for over 2½ years running the slower FSB speed CPU and memory. That was about to change...." (Is this true?)