>Hi Al ( & Ric)
>
>>>
>Having said all that, PM processors are still very uncommon in desktop PCs. The whole industry is currently very unsettled in what it calls "speed ratings" (in your case the 2.8GHz figure); it might be that even Intel differentiates actual processor clock speed from "speed ratings" amongst its own processor (and processor core) families.
>>>
>
>I found some software from SiSoftware that gives quite a bit more detail on the hardware values on the machine in question. On the processor it gives:
>
>Model: Intel(R)Pentium(R) 4 CPU 2.80GHz
>Speed: 2.1GHz
>Rated speed/FSB : 2800MHz / 4 x 133MHz
>Name: P4N (Northwood) Pentium 4C 130mm 1.6-3.4GHz 1.475-1.575v
>
>But for the motherboard chipset:
>
>Front side bus speed : 4x100MHz (400MHz data rate)
>Maximum FSB Speed / Max Memory speed : 4x100MHz / 2x133MHz
>
>Is it the latter that prevents the processor running at full speed ?

Most modern motherboards have BIOS settings that let you control CPU speed. Most of the time these settings are "Auto" which runs CPU, front side bus and RAM at maximum rated values as determined by the components themselves.

It may be that on that machine the BIOS speed settings have been set manually to a lower-than-maximum figure. This could be because:

- machine doesn't work at all, or is flaky at "rated" speeds. Basically someone hasn't bothered to track down the hardware problem, they just de-tuned the speed until things work again

- there have been a few cases of builders buying chips that failed rigourous testing, then installing them in systems with de-tuned speed settings. These sometimes show up in "too good to be true"-cheap desktop PCs. Hopefully this is not your case, otherwise the whole machine is questionable.