[vox] x86-64: AMD, intel and compatibility

[Shwaine]

On Wed, 17 Sep 2003 p@dirac.org wrote:

> hi all,
>
> tom's hardware hints that the new 3200+ is the last 32bit athlon (and
> it got _trounced_ in the reviews.).  since i won't be ready to build a
> new computer anytime soon, my next computer is probably going to be an
> AMD x86-64 machine.  that's kind of a scary thought.
>

Well, remember to take any of these benchmarks with a HUGE grain of salt.
Remember all the AMD accusations that Sysmark changed its software to
routines that favored Intel's processors from a while ago. Most of the
evidence was rather compelling. And Tom's does use Sysmark. Plus, you
throw in the differences in the motherboards and the other variables and
it becomes quickly apparent that such comparisons are about as good as a
cell phone's advertised battery life. For example, their nForce2 chipset
drivers are horridly out of date (current 2.45, tom's 2.02 which is over 9
months old) and I seem to remember hearing driver issues with the older
drivers (and the newer ones for that matter too).

> so i've been wondering about these questions...
>
> if the itanium-1 isn't x86-32 compatible, and the itanium-2 is very slow
> at x86-32 compatibility, how does intel propose to stay in business?
> are they really banking that we'll all throw away our 32 bit software?
>

I can think of several companies/groups/people who would just love to
force people to throw away all the 32-bit software. Of course they're
living in a fantasy world, but that's for another thread. Most likely
they'll just say live with the bad performance or keep the old machines if
you want your 32 bit programs (kinda like the problems with older DOS/Win
3.x programs on newer systems, look how well that went).

> are the AMD x86-64 systems really supposed to achieve 100% 32bit
> software compatible?
>

Haven't looked at it in detail, but that's what I've heard. Haven't heard
a peep on how efficient it is at the 32bit emulation either.

> and what about hardware?  can i just stuff all my PCI and ISA cards into
> a motherboard designed for an AMD x86-64?  IDE stuff?  SCSI cards?  the
> works?
>

Again, not a hardware expert, but from my experience with my Alpha (64 bit
processor) the PCI cards were freely interchangable. Data buses I believe
are independant of the CPU addressing scheme, but don't hold me to that,
heh. My dad's the hardware person in the family. I stick to networks and
security.