64bit processor question.

Hi.

There's a lot of talk about 64bit processors.

But is the motherboard 64bit, I mean a 64bit data bus.

Just an 32bit bus and an 64bit processor is not optimum.

I have an early 32bit CoreDuo processor the new versions are 64bit.

Is their much difference between the two, if they both have an 32bit data bus.

regards.

John.

 

There's a difference between the two simply because the newer processors (Merom core) are designed better so they will perform 10%-15% better than en equivalent Yonah core.

The motherboards aren't 64bit, just the cpu.

 

Actually, I believe the Hypertransport bus used by AMD is 16 bit.
Not sure about Intel's FSB though. Might be 32, but then it has a correspondingly lower clock speed.

Still, bus width doesn't matter too much (or rather, of course it matters, but it's no big deal whether it matches the CPU bit width).
First, instructions aren't 64 bit in any case, second, most data is still 32-bit. And third, memory accesses are rather uncommon, and most of the time, the required data can be fetched from the CPU's onboard cache (The bus between CPU and cache is something like 128 bits wide, I think)

But generally speaking, the memory bus and the CPU do not have to run in sync, and so relative speed and bit width doesn't matter too much. And when a PC CPU is 64-bit, it really only means it *supports* 64 bit operations. Not that 64-bit is the default. The "standard" datatype is still only 32-bit.