Carzy Zarx’s PC Gaming Emporium - Catch Up on All the Latest PC Gaming Related News

[Pemalite]

Bofferbrauer2 said:

Pemalite said:

Older instructions have also slowly been removed over time.

Case in point... 3D Now! is no longer in modern CPU's, so the only way those programs/games can run, is that they must emulate that extension... And some CPU's MMX is translated into SSE instructions and so on.

x86 is great for high performance, high frequency computing, which is why it has remained a step ahead of PowerPC, ARM, MIPS in the performance stakes.

Yeah I know, just didn't want to go too much into details. Much of the original x86 instructions and many pre-MMX extensions (386, 486 and the original pentium got some small additions) are gone, too.

Makes you wonder if the old adage that you could in theory downgrade any x86 processor all the way down to an 8086 if most of it's original instructions et is missing...

In theory you can, but you would need to waste clockcycles on emulating.

For instance, there is about a 10x performance penalty emulating 3D Now! instructions verses doing it on the SIMD units, but it doesn't matter much when a modern CPU operates at 17x the frequency of the early AMD K6-2 300's with probably just as much IPC increase.

But the biggest issue is that modern PC's have simply moved on, we don't run ISA or even PCI slots anymore, we don't use EDO Ram, we don't even have Sound Blaster! Compatible audio anymore (Creative emulates it these days), we don't have COM, LPT1/Parallel ports anymore... And old 286/386/486 software actually relied on the CPU's clockspeed to determine the "tick rate" aka. Running speed of software and games. (Hence why they added a Turbo button to older computers.)

So it's just easier to virtualize all that stuff in a software environment... Or for industrial applications you can go out and grab a PC/104 system which has a 286/386 or 486 clone CPU (From the likes of SGS-Thomson) or grab an Vortex86SX system... Which are great for Win95/98 stuff.