Linked by Nicholas Blachford on Wed 9th Jul 2003 16:43 UTC
Talk, Rumors, X Versus Y This article started life when I was asked to write a comparison of x86 and PowerPC CPUs for work. We produce PowerPC based systems and are often asked why we use PowerPC CPUs instead of x86 so a comparison is rather useful. While I have had an interest in CPUs for quite some time but I have never explored this issue in any detail so writing the document proved an interesting exercise. I thought my conclusions would be of interest to OSNews readers so I've done more research and written this new, rather more detailed article. This article is concerned with the technical differences between the families not the market differences.
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Re: Goo
by bobby on Wed 9th Jul 2003 19:43 UTC

Intel pushed the 8088 as the "next" 8080 while the Z-80 was Zilog (loaded with former Intel engineers) vision of what the next 8080 processor should have been. The 8086 was just an 8088 with a 16 bit data bus. I do not know if the binary's were compatible, and I know the mneumonics were extended, but the idea was to be able to use your 8088/8086. If there were such drasic differances, then it would be my guess that Itel missed the mark. But from what I have seen, the 80486 and 8080 appeared very similar at the assembly level (Sorry, I have not done much intel assembly to have a real feel for it). I only encountered the 8080 codd because we used a C compiler that generated 8080 assembly to run on our Z-80's 15 years ago.

But the bootom line is that Intel intended the 8088/8086 to be a 16 bit extension of their 8 bit 8080 which came from the 8008 that owed it's start to the 4-bit 4004 processor used in early calculators.

They transistioned to micro-coded architecture with everyone else in the 80's. But the architecture was not improved by it. It just allowed the architectuer to be extended one more time. The old Single accumilator design persists even in the P4. The x86 line is a 1970's arcitecture that has been tweaked into the future. The PPC is a 1990's architecture that is near the beginning of it's life. Designed from day 1 as 64 bits (The 32 bit processors are implimented as a 64 bit processor with the extra bits removed). The x86 is an 8 bit arcitecture that has been extended to now, so the A register was extended to 16 bits by renaming the A as AL and adding an AH, then when they went to 32 bits, they attached another 16 bits and call it AX.

You still have to shuffle the registers so that all math involves the AX register. You still have All the segment register nonsense to maintain compatability with the 80186/80286 attempts at 32 bit operation. With the 80386 they added flat 32 bit memory.

Do not get me wrong - Intel has done a wonderful job at keeping the platform going - I have been declaring it dead since the 80286 came out. But they keep tweaking the speeds up. But the Itainium is their concession to the eventual death of the architecture. AMD seems to want to keep it alive by broviding for effiecent operation of 32 bit code.

Bottom line - The x86 is like an old 60's muscle car. They have tweaked the engine so that it has the spead of a sleak new Porsche ... But the Porsche does it with an engine that is half the size and double the gas mileage.

The x86 is bigger requires twice the clock speed, generates 4 times the heat do do the same amount of work as the PPC. They may be about the same speed, but the PPC has a lot more room to grow.