PowerPC: The RISC Revolution That Might Dethrone Intel
The "AIM" alliance (Apple, IBM, and Motorola) has finally delivered on its promise. I’ve just had some time with the new Power Macintosh 6100, and the speed is incredible. We’ve been living in an Intel-dominated world for so long that we forgot what a clean-sheet architecture could do. PowerPC is here, and it’s bringing the RISC (Reduced Instruction Set Computer) philosophy to the desktop.
RISC vs. CISC
The Intel x86 architecture is "CISC" (Complex Instruction Set Computer). Over the years, it’s accumulated hundreds of weird, specialized instructions that are a nightmare to optimize. PowerPC takes the opposite approach: a smaller set of simple instructions that all execute very, very quickly.
Because the instructions are simple, the processor can use "superscalar" execution—running multiple instructions at the same time—much more efficiently than a Pentium can.
; PowerPC assembly is remarkably clean and regular
lwz r3, 0(r4) ; Load word and zero
add r5, r3, r6 ; Add two registers
stw r5, 4(r4) ; Store word
On an x86, an ADD instruction might have to deal with memory operands, different sizes, and complex addressing modes. On PowerPC, everything is register-to-register, which makes the pipeline flow like water.
The Emulation Miracle
The most impressive part of Apple's transition isn't the native speed—it’s the emulation. Most of the software we use today is still written for the old 68k Macs. Apple built a 68k emulator into the ROM that is so fast, most users can't even tell their old apps aren't native. It’s a masterclass in how to handle a platform transition.
Looking Ahead
Can PowerPC actually beat Intel? On a technical level, it already has. The performance-per-watt and raw throughput are superior. But Intel has the "Wintel" monopoly and a massive manufacturing lead. As a developer, I love the elegance of the PowerPC architecture, but I know the battle will be won in the market, not the lab. Still, if I’m doing high-end video or graphics work today, there’s no question which machine I want on my desk.