If you haven’t already, check out Tom Yager’s
IBM’s Power5 worth a second look, first posted on MacCentral on December 22nd.
The Power5 hasn’t yet arrived in an Apple machine, despite the similarly named PowerPC G5, the Mac’s latest, greatest CPU. Apple’s G5 is actually based on the Power4 — except with a single core, a smaller die, less heat, and lower power consumption.
In other words, the PowerPC incarnation of the Power architecture is optimized for smaller machines. And that plan seems to be working better than ever: Apple sold 836,000 PowerPC laptop, desktop, and server systems in its fourth fiscal quarter of 2004. That’s no threat to Intel or AMD, but then there are no $400 Macs for sale at Wal-Mart Stores Inc., either. After x86, there is little question as to which CPU architecture will retain the No. 2 slot. (Hint: It’s not Itanium 2.)
Back in the early ’90s, it was Apple’s desire to move beyond the performance limitations of the Motorola 68xxx line of microprocessors that led to the creation of the Somerset project in Austin, Texas. There, engineers from Apple, IBM, and Motorola Inc. (AIM) collaborated and fought with one another (mostly fought) to create the first PowerPC, the 601, a single-chip derivative of IBM’s high-performance RS/6000 CPU. As soon as the processor shipped, Apple began delivering the first model of Power Mac. That initial PowerPC-based machine outsold Intel-based PCs, helped by the fact that Apple and Motorola developed tools that generated “fat binaries,” software that ran identically on 68xxx and PowerPC-based systems. (Hello, Intel?)
Apple is still the driving force behind discrete PowerPC engineering. It drove Freescale, a Motorola spin-off, to create the MPC7447A to replace the inefficient CPU used in the first 17-inch PowerBook G4. Freescale’s next work will be the 7448, which doubles the cache size of the 7447A and raises the ceiling on the bus and clock speeds. The company also has a dual-core, 32-bit PowerPC chip coming up.
Apple drove IBM to create the 64-bit home runs PowerPC 970 and 970FX, chips that, similar to the 601, appeared in Apple hardware in record time. Power Mac G5, Xserve G5, and OS X did for Mac users what even the brilliant AMD can’t do without Microsoft’s help: migrate users to a 64-bit platform without one bump. Just as intriguing, Apple, IBM, and the public partners that sign IBM’s open license could carry Mac users all the way to Power without the suffering that blocked users’ migration from x86 to Itanium.
PowerPC and Power form a continuum of compatible, and now open, processor designs — and our guess is that the Power5 design will arrive in some form in an Apple machine in 2005. The companies that rely on PowerPC will do very nicely betting on the No. 2 horse.
Tom Yager is technical director of the InfoWorld Test Center.