Please help ,Motherboard question

[Lyndon]

Please can someone give me an answer to a question at college i just cant get my head round. Q if you fitted a 550Mhz processor to a new motherboard what would be typical speed for the memory bus and what multiplier would you choose. :confused: :confused: :confused:

[123456]

It depends on the motherboard and processor specifications. What are the features of the processor and mobo? What kind of processor is it, (Intel PIII/Celeron), and what brand is the motherboard?

bTW, welcome to http://www.pcguide.com/ubb/pcgubb.gif

[saphalline]

CPU's get their speed from two things: the speed of the FSB (or system clock) and the multiplier they use on the FSB. For instance, the Pentium 120 was clocked at 120MHz. It used a 60MHz FSB speed. So from that, we can conclude that it had a 2.0x multiplier.

2.0 x 60MHz = 120MHz CPU clock.

To answer that question you got at college effectively requires some background knowledge of computer technology at the time that CPU's were in the 500MHz range. I know a lot about that stuff, so I knew the answer right away. But obviously you're not a hardware historian like I am. ;)

There's a few key clues in that question that really give things away. First of all, the use of the word "typical" to describe the settings. Typical is another word for Intel! :p Intel dominated the CPU industry back during the 500MHz era. Another implication of this Intel focus is that the multiplier for the CPU was locked by that time. In other words, the CPU in question is designed to run at 550MHz but more importantly it has a specific unchangeable multiplier that is applied to the FSB in order to get to 550MHz. If you use a different FSB speed, the multiplier stays the same so you get a different CPU speed (either faster or slower depending on which way you change the FSB speed). The final clue here is the speed of the CPU. 550MHz is a dead-give away for the specific settings used. The only way to get to 550MHz with a nice multiplier is to use a 100MHz FSB. This was common back then for a PIII in the 500MHz range, because the lower-end Celerons were using the 66MHz FSB (partly to relegate them to a lower performance bracket) and the PII's stopped at 450MHz. Also, SDRAM was prominent by this point, and PC100 SDRAM was designed to run at 100MHz. So now that you know the FSB speed, and the corresponding convenient RAM speed, what do you think would be the locked multiplier for a PIII 550?