CPU Question

zach1288

1. Say i have an AMD Athlon XP 2800+ the external data bus size is 32-bit the address bus is 32-bit and the registers are 32-bit, Since it is a "32-bit" CPU correct?

2. And if i have an AMD Athlon 64 2800+ the external data bus size is 64-bit the address bus is 64-bit and the registers are 64-bit, Since it is a "64-bit" CPU correct?


3. And one last thing. If each register is 32-bit or 64-bit in a CPU and there are 4 registers would that not make the CPU a 128-bit processor or a 256-bit processor?



-Zach

Plantwiz

zach1288 wrote:

1. Say i have an AMD Athlon XP 2800+ the external data bus size is 32-bit the address bus is 32-bit and the registers are 32-bit, Since it is a "32-bit" CPU correct?

2. And if i have an AMD Athlon 64 2800+ the external data bus size is 64-bit the address bus is 64-bit and the registers are 64-bit, Since it is a "64-bit" CPU correct?


3. And one last thing. If each register is 32-bit or 64-bit in a CPU and there are 4 registers would that not make the CPU a 128-bit processor or a 256-bit processor?



-Zach

HI Zach,
I have about 1 minute to answer before I leave, but I'll elaborate more tonight.

Basically, Yes, on 1 and 2. The AMD 64 is a 64 bit CPU and can support a 64bit OS. It is also backward compatible.

I'll be back tonight.

daking

Hmm think Plantwiz got it wrong.

1. Say i have an AMD Athlon XP 2800+ the external data bus size is 32-bit the address bus is 32-bit and the registers are 32-bit, Since it is a "32-bit" CPU correct?

No, every cpu since the Pentium has a 64-bit external data bus. The address bus and registers are 32-bit.

2. And if i have an AMD Athlon 64 2800+ the external data bus size is 64-bit the address bus is 64-bit and the registers are 64-bit, Since it is a "64-bit" CPU correct?

First difference in 64-bit cpu's is the address bus is going to be 64-bit. When I mean going to be, is cause they started of as lower values like the Itanium have 44-bit address bus. This is because that much memory (2^44) can't be even worthwhile to address presently. You are right though that the registers are 64-bit already and set for the future for a full 64-bit address bus.

Plantwiz

Yes, daking is correct about the bus vs bit.... I didn't read the question thoroughly as I was walking out the door seconds before answering and had planned to return here with a better answer.

You may find this to be of interest:
Difference between 64bit and 32bit CPU's

AMD64 vs 32bit processors

AMD64 vs P4 Extreme

AMD64 vs. P4 Extreme another

AMD's announcement

MS Windows 64 bit OS

summary of CPU bus speeds

Cache


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AMD
http://www.amd.com/us-en/Processors/SellAMDProducts/0,,30_177_3472_1394^7538^4549,00.html
AMD's 32bit CPU

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For your third question...128 and 256bit processor...still working on getting there So maybe by 2006-2007 we may see things moving in that direction.

Still I doubt this answers your why??? about it. I'm working on it