Processor Core Speed or Bus Speed - what's the difference, please?

Question

I've just found out my PentiumIII processor has two different speeds, namely:

Core Speed of 731 MHz
and,
Bus Speed of 133 MHz.

I want to buy a PCI tuner board that needs a processing speed of 500 MHz (or greater), but do they mean Core or Bus speed?

I'm too stupid to know the difference, can you advise please (or point me to an idiot-proof help site)?
Thank you.

Answer 1

The CPU or processor speed is what they are referencing. The core speed is the speed of the processor and the bus speed is the speed of the PCI bus in the case of the 133 MHz number. There's also the memory bus speed which on your system is 133 Mhz. If your RAM is rated at 266Mhz, that means it operates at 2x the memory bus speed. In the case of CPU rating, if your CPU is rated at 733Mhz, that would be a clock multiplier of 5.5x the bus speed (5.5x133=733, approx.).

Answer 2

The Front Side Bus (FSB) is the connection between the CPU and system memory. The Front Side Bus operates at a speed which is a percentage of the CPU clock speed. The faster the speed at which the Front Side Bus allows data transfer, the better the performance of the CPU. Do not forget the L1 and L2 cache sizes! The purpose of a cache is to enable the CPU to access recently used information very quickly. A cache will significantly affect CPU performance. However, caches also represent some difficulties in simple comparison. Some caches are bigger than others. A typical L1 cache is 256Kb and a typical L2 cache is 1MB. Generally speaking, the larger the cache, the better the system performance boost. However, this is not always the case. A cache operates at a certain speed, just like the core of the CPU. Some caches operate at the full speed of the CPU, while others operate at half that speed or less. A small cache which operates at full speed may be much more useful than a cache which is twice as large but operates at only half the speed of the CPU. Even comparing cache sizes can be difficult. Some CPU's utilize inclusive caches. In a CPU with an exclusive cache, the data stored in the L1 cache is often duplicated in the L2 cache. Only CPUs which employ exclusive caches will have the full capacity of their L2 caches available. I hope this helps

Answer 3

PCI works in a fixed speed of 33 MHz, it is attached to the Southbridge of the mobo and not related to Core nor Bus speed, a tuner in fact works in less than 5 MHz. But just ignoring all these speed setting, you have no choice.

Answer 4

They really are what they say - the core speed is the timing clock frequency the CPU uses to process data internally and the (forward side) bus speed is the timing clock frequency the CPU uses to communicate with the outside world.

Despite being for a PCI card, external to the CPU, they are talking about the processor's core speed here.

Answer 5

Hi.

The Core speed that is reported refers to which the CPU runs internally.

As it has connections to peripherals (memory, PCI, ...) and they have lower speeds, the Bus Speed referes to that used for those connections, but it only matters when you need to add extra memory or when in your computer you need to install and AGP graphics card (2x, 4x, 8x)

When any HW manufacturer refers to Processing speed, they are talking about Core Speed.

Don't be worried, it could work.

Answer 6

The core speed is more important. The tuner you are looking at will be referring to the core speed.

Answer 7

basically the core speed is the processor speed, which is what, in general is most important. where as the FSB is the speed that the processor speaks to other components rather

Answer 8

They mean Core speed so your Pentium will do.

Answer 9

core

bus speed is probably never mentioned when it comes to system requirements