CPU frequency question

I recently got a new Celeron 2.4 GHz CPU along with a new motherboard. On the CPU box it says “400 MHz system bus.” On the motherboard box it says “supports 800 MHz FSB.” The BIOS setup screen tells me it’s running the CPU at “100 MHz x 24”. Does the “100 MHz” and “400 MHz” refer to different things, or is this CPU running below its optimal speed?

Normally I do more resarch before purchasing but I needed to replace a dead motherboard quickly.

I think 100Mhz x 24 means it’s running at 2.4 Ghz (as expected). Not enough info to determine the bus speed… ?

You bought a Celeron. That is bad news to begin with. Celerons generally only support a 100 MHz Front side bus (“quad pumped” to 400 MHz effective - 4 data transfers per cycle). In addition they have limited cache which is critical to the simplistic instruction set but long pipeline of the Pentium architecture. Your Celeron is running as well as can be expected.

You motherboard will accept, in addition to Celerons, true P4 processors which have more cache on board. In addition P4’s come in “A” versions (100/400 MHz), “B” versions (133/533 MHz) and “C” versions (200/800 MHz). IMHO, the only Intel systems worth investing in are ones with P4C processors and MB’s with 800 MHz capacity. Of course, as you can probably guess, all my computers except the notebook the company gave me are AMD Athlon powered.

Ah, that explains it, thanks.