Q I have been reading with interest your review of some BX chipset motherboards, and I wonder if you would mind clearing up just one point.

A There are two clocks associated with any Pentium or later processor. There is the internal clock, which is how fast the processor runs. There is also the clock that dictates how fast the processor talks to external things like memory. This is often referred to as the clock speed of the motherboard. For older Pentium computers the clock speed was for a long time around 50û66MHz.

The faster the clock speed of the motherboard, the faster the RAM SIMMs (or DIMMs) need to be. However, SIMMs don't have a clock speed. Rather they have a rating according to how fast you can access information from them. For motherboards with a clock speed of up to 66MHz, you only needed 70ns RAM. The introduction of processors that had an external clock speed of 75MHz meant that the RAM needed to be at least 60ns. With 83MHz motherboards you need 50ns EDO RAM. Unfortunately, this is the upper limit for EDO RAM, and with a motherboard clock speed of 100MHz you need SDRAM. If your RAM is 10ns, then it should work happily in your system.

If you have some RAM and you are wondering how fast it is, diagnostic software isn't much help. When the RAM is in your computer, it runs at the computer's speed; diagnostic software such as WinCheckit can only use the hardware as it is set up.

It is worth nothing that you can use slower RAM in a system by adjusting processor wait states. This is a period of time in which the processor does nothing while it waits for the slower memory to "catch up". However this is not a recommended solution as it slows the system down. It is possible to upgrade your processor, increase the motherboard clock speed, keep using your slower RAM with wait states, and achieve no increase in overall system performance.