FS2004 on a 64-Bit Processor?

[CHANGE USERNAME TO westes]

Someone else posted this review of MegaScenery, and what catches my eye is
that the reviewer was able to run FS2004 on an AMD 64-bit processor:

http://www.flightsim.com/cgi/kds?$=main/review/mega3.htm

How is it possible that a 32-bit Windows and application written for a
32-bit environment worked on a 64-bit CPU?!

--
Will
westes AT earthbroadcast.com

[Tom Orle]

AMD CPU's are backward compatible - the 32bit code just doesn't take
advantage of the new 64bit features.

INTEL CPU's require a 64 bit operating system which is in the works.
-=tom=-

[CHANGE USERNAME TO westes]

So do you get any performance advantage running 32-bit OS in a 64-bit
processor? I'm not understanding the Megascenery review I linked in the
original post making the claim that the system that used the 64-bit
processor loaded four times faster.

If you run Windows XP 64-bit on the 64-bit AMD processor (Microsoft is
already distributing this code on their web site for beta testing), will you
be able to run Windows 32-bit applications, and will those see any
performance advantage?

--
Will
westes AT earthbroadcast.com

"Tom Orle" <xspam...@att.net> wrote in message
news:m2m6k09v4sqssobon...@4ax.com...

[Lars Møllebjerg]

"CHANGE USERNAME TO westes" <DELETE...@earthbroadcast.com> wrote in
message news:dK-dnRqRRMu...@giganews.com...

> So do you get any performance advantage running 32-bit OS in a 64-bit
> processor? I'm not understanding the Megascenery review I linked in the
> original post making the claim that the system that used the 64-bit
> processor loaded four times faster.

The 64 bit AMD processors generally have a larger cache than the 32 bit
processors - hence they will run faster - but they are not necessarely
faster than a similar 32 bit processor with identical cache.

>
> If you run Windows XP 64-bit on the 64-bit AMD processor (Microsoft is
> already distributing this code on their web site for beta testing), will
> you
> be able to run Windows 32-bit applications, and will those see any
> performance advantage?

Yes, you will be able to run 32 bit code. The 64 bit instructions are
additional to the 32 bit instructions - so 64 bit programs might use these
instructions, 32 bit programs will not. A 64 bit version of Windows will
internally use these 64 bit instructions as well, and it migt offer some API
calls using them as well (never bothered to check, but it is possible)..

Notice that on old 64 bit CPU's (yes, 64 bit have been around for ages - in
fact the oldest computer I still have running has a 64 bit processor) you
had situations where a program compiled for 32 bit would perform better than
the same program compiled for 64 bit. I have no idea if this is still the
case, but it would not surprise me - a 32 bit program might fill the cache
with less useless zeros.

The move to 64 bit is in no way a revolution (if it was, DEC Alpha
processors would have been the leading server processors). If the program do
not need any integers over 32 bit (and most don't) there isn't any real
benefit using 64 bits. The main advantage of 64 bit is addressing over 4GB
af memory - something primarely done by database servers.

/Lars

[Tom Orle]

Some of the internals will be faster, CPU internal processes to cache
memory, etc , or regular memory acces and northbridge/southbridge
communication if the BIOS and MB support it.

Maybe even data transfer to your graphics card might improve a bit.
But the program itself will not run faster.

Just my opinion ...

-=tom=-

"CHANGE USERNAME TO westes" <DELETE...@earthbroadcast.com> wrote: