Wednesday, June 09, 2004


Apple has just announced its new Power Mac G5 lineup. and the only thing I can say is I'm impressed. Not only have the clock speeds beeen ramped up to a maximum of 2.5 GHz, but the entire product range now consists of dual-CPU machines. Here's one more respect in which Apple is ahead of the PC crowd, where 2-CPU machines continue to be restricted to the server and high-end workstation market.

One thing to note: though the 2.5 GHz CPU speed on the top of the line G5 might not seem like a lot in the current era of 3.4 GHz Pentium 4 processors, the really important thing is the amount of work that a machine can execute in a given time, which is a measure of IPC multiplied by clock speed. One consquence of the PowerPC's cleaner RISC design is that its IPC count is higher than that of the x86 alternatives, so a single-CPU PowerPC running at 2.5 GHz is actually comparable if not faster at most tasks than a Pentium 4 running at 3.4 GHz. It's also worth pointing out that the fastest AMD chips out are also actually running at 2.4 GHz.

The rough parity between the fastest chips from IBM, AMD and Intel isn't surprising once one takes into account that they're all using essentially the same process technologies, and none of the three has such a stranglehold on design talent as to be able to outrace the others for very long. The difference between Intel and the other two CPU vendors lies in the conscious decision by Intel to trade off IPC for higher clock speeds, with the expectation in mind that most consumers are so taken in by raw Megahurtz [sic] that they'd be fooled into thinking the Intel offerings were superior. While this probably did do the job with the most ignorant consumers, for the most part it seems to have failed, as AMD hasn't really ceded any market share to Intel in the desktop sector.

At any rate, what's really holding Apple back at present isn't its chip architecture but the quality of its compilers. GCC is a marvelously complete, portable and standards compliant compiler, but unlike Visual Studio .NET 2003 or Intel VTUNE, it was never designed to extract every last ounce of performance from any particular CPU architecture. IBM certainly has the requisite compiler technology to squeeze big gains out of the CPUs it's delivering to Apple, so I don't see what is preventing the licensing of these tools to the broader Apple developer community, even if at an appropriately hefty price.

ADDENDUM: I spoke too soon. IBM has already released the necessary software for the OS X platform.


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