X86 vs X86-64
 

Hey, very simple post. I came about X86 and X86-64. To me the 64 would mean 64Bit?

But under X86-64 it had things like P4 extreme and Pentium D's. Pentium D's are dual cores i think (i dont keep upto date with computers these days), so is a dual core intel classed as X86-64?

I have a Intel Centrino Core Duo, i am guessing this is just X86, but core duo is part of the D range i think, dual core, so is it X86-64?

Please unconfuse me...

32 bit is 32 bit, 64 bit is 64 bit.

Whether it's single core or dual core or hyperthreading or whatever is orthogonal to that.

To understand what a particular chip does, look it up on the manufacturer's web site.

I think all these chips do run the basic 8086 code though.

That's where AMD stole the market share from Intel: maintaining backward compatibility with 80x86 opcodes. Intel tried to go in a different direction, but as soon as you can't run good ole Windoze (especially the bootleg copies that most of the world is running) you consign yourself to a very niche market (commercial servers, basically).

planecrazy.eu

Good question - what you ask is not easily answered! Even Intel is (possibly deliberately) vague about what the answer is.

Does Intel do 64-bit?

Not always so - some processors can be either 32 OR 64-bit depending on what OS is running on it! If you boot up a 32-bit OS, the processor will operate in 32-bit mode only and will NOT run any 64-bit code. You can boot the SAME processor with a 64-bit version of the OS and it will run BOTH 32 AND 64 bit code.

IO540, it wasn't the backwards compatability that allowed AMD to leapfrog intel - it was that AMD could sell a 64-bit processor that also ran 32-bit code as fast as (or faster than) a 32-bit processor.

At the time, intel's 64-bit offerings (think Itanium cores) ran 32-bit code like treacle.

There was never any question of intel 64-bit CPUs not running mainstream COTS OS and applications, just that they weren't particularly good at running 32-bit code - and there was little native 64-bit code around for them to show how good they were at that!

Intel has more than caught up with AMD - it has passed it by with its dual-core CPUs running faster and (crucially) significantly cooler, hence lower running and cooling costs.

SD