64 bit architecture

[snow]

Ok, what exactly is 64 bit about these new processors

the bus width has been 64 bit since the Pentium Pro's, so I'm wondering what is exactly is 64 bit vs the old 32 bit variety.

Clueless,

snow

[piasabird]

So far the oper syst is still 32 bit. Doesnt do mush good to limit a processor capable of handling 64 bit to 32 bit. The processor is often cablable of 64 bit but not taking full advantage of it. For instance is the AGP Port and the PCI bus 64 Bit? Only sometimes. While some memory buses are 128 bit. There are some server boards where some PCI slots are 64 bit for fiber optic boards.

[GaryRouth]

Here's an article on "Myths & Realities of 64-bit Computing" over at AnandTech.com

http://www.anandtech.com/guides/viewfaq.html?i=112

Since Hammer is almost here (and a newer Itanium as well), interest is growing. 32-bit cpu --> 64-bit cpu: the difference can be thought of in the range of numbers that can be computed: true for both integer and floating point. The article covers it better than I can, give it a read.

By the way, just like here at PC Mechanic, there are some other good articles in the AnandTech FAQs, too. I recommend them.
. . . Gary