What does System Bus Speed mean when referring to CPUs?

Question

I am looking to beef up my OLD computer a little. I have a motherboard that supports Intel Pentium 4 (Socket 478) Processors. My current processor is a 1.5 GHz, 400 MHz System Bus.

While looking at possible replacements online, I see all kinds of Pentium 4 (Socket 478) processors but they all list different System Bus speeds. Some are 400 MHz, some 533 MHz, some 800 MHz.

My questions are... What does the System Bus speed really mean? What is better? Can I put a 800 MHz chip in place of my current 400 MHz chip or am i limited to only 400 MHz?

Answer 1

The bus speed is basically how fast the data is transferred across the board to other devices such as the video card, north bridge etc.

With Pentium 4 systems, you are generally going to be restricted by the bus speed when you are trying to upgrade. Your motherboard will most likely not support any bus speeds faster than 400MHz.

But, these days you can get some of the older (older being a year or two) motherboards for rather cheap off of Ebay and other such places. Many of these boards will have support for the faster processors.

Answer 2

Your bus speed is the speed in which your processor can communicate with the other components in your system. The bus speed is determined by your motherboard. The only way to increase the bus speed is to replace the motherboard.

Answer 3

The system bus is the speed it communicates with the RAM. The faster the better, but it all depends on your motherboard, it might not handle the faster bus speed.