Front Side Bus Posted by shariq shukur , Tuesday, June 9, 2009 at 5:43 PM, in

Front Side Bus

The term which describes a Processor to System Memory Data Bus is known as Front Side Bus. The other Synonyms of a Front Side are System Bus, Memory Bus, External CPU Speed and CPU Bus Speed. The speed which Communicates with RAM is the Front Side Bus. The Front Side Bus on a Computer connects the processor to the North Side Bridge, which comprises the Memory Bus, PCI Bus and AGP Bus. Moreover a higher Processing Speed and Faster Computer Consist of a Faster Front Side Bus.

In Pentium 4 the Front Side Bus Consist of 400 MHZ, but it is the fact that 100MHZ "Quad Pumped". The Data is transfered twice per a clock cycle, on the rise and fall edge and can also transfer two bytes of data at a time to effectively give four times the throughput of a 100MHZ Front Side Bus. A Clock Multiplier is applied to the Frontside Bus Speed to determine how fast a processor runs.

For instance a processor running at 550MHZ might be using 100MHZ Front Side Bus. the clock multiplier might to 5.5. Thus a CPU is set to run at 5.5 times the processors are available in multiples of 100MHZ, 133MHZ, 266MHZ, 333MHZ and now with the AMD KB 3200+ and AMD Athlon FX-51 1600MHZ FSB.

By changing the Jumper a user can manually set the clock Multiplier and FSB settings. This ablity is provided by some Motherboards. The preset multiplier setting are locked by some manufacturers which disables the user to set the clock. A FSB speed for the CPU purchasing should consist of memory capable of this faster speed. Pushing the front side bus to 110MHZ means you are also pushing your memory, be it PC100, to 110MHZ. A FSB today is dual or quad channel, a FSB speed advertised as being "333MHZ" may actually be 166MHZ dual channel, effectively means 333MHZ of speed. CPUs work with front side bus speed ranging from 133MHZ dual channel to 200MHZ quad channel.