Megahertz Myth: Power5 Desktop Edition May Debut at 'Only' 1.5GHz


A DP 1.42GHz Power Mac with all the fruit may be the fastest Mac on earth, but proving once and for all that clock cycles aren't everything is IBM's Power5, currently in prototype form.

Like the PowerPC 970 - the desktop edition of the Power4 - the Power5 is a 64-bit chip. However, whereas the Power4 is almost-literally '2 chips in one', the Power5 is four. The Power5, like the Power4, is dual-core, but it will appear to the OS as four processors, says a story at The Inquirer.

The key addition to Power5 is multithreading, a technology which permits the CPU to run two or more parts of an application simultaneously. The desktop editions of the Power5 will be equipped with only a single core, but it will support multithreading.

Adding more fuel to the megahertz myth fire is the fact that IBM has reportedly established the goal of quadrupling the performance of the Power4.

Analysis: As we can assume that Jobs has seen this particular PowerPC road map, the deployment of Power4 and Power5 in desktop Macs - and XServe of course - is likely to be delayed only by how quickly Apple can make OS X take full advantage of the CPU's capabilities. The second challenge will be encouraging developers to move their apps to 64-bit (both the PowerPC 970 and the Power5 desktop editions will be fully backward compatible with 32-bit OSes and apps). But if Apple leads, Adobe, Macromedia and others will follow.