Apple downgrades Power Mac CPUs – but not their prices

Motorola blamed -- again

Apple yesterday tacitly confirmed the existence of a major bug in the PowerPC 7400 (aka G4) when it admitted it had been forced to reconfigure its Power Mac G4 line -- downwards. However, the pricing for range remains the same. Each of the three models in the G4 family have been downgraded by 50MHz. Instead of 400MHz, 450MHz and 500MHz models, Apple's catalogue now contains 350MHz, 400MHz and 450MHz machines. Apple said the move had been made in response to Motorola's current supply of processors to allow it to meet demand for the Power Macs sooner rather than later. Apple admitted it would not be able to ship 500MHz machines until next year because the "500MHz G4 processor will not be available until the first calendar quarter of next year". The 500MHz Power Mac was original due to ship by the end of this month, but, as online magazine MacWeek discovered, a bug in the current G4 silicon prevents the chip from being clocked to 500MHz without experiencing corruption of the chip's data cache. The effects of the damage to data range from crashes to a significant reduction in the speed of the machine. However, despite knocking 50MHz off each model's speed, Apple has not knocked anything off their prices. Of course, with RAM prices rocketing, that's perhaps not surprising, as any gain in processor costs is balanced by an increase in the cost of memory. Still, actually offering a lower clock-speed -- the 350MHz version -- suggests Apple has to take what it can get because Motorola is having problems shipping sufficient quantities of 450MHz parts and possible even 400MHz chips. Like all other chip vendors, Motorola will test each chip that comes off the production line. Each chip is run through the range of clock speeds and is approved for operation at whatever speed it reaches: if it doesn't run at 450MHz, it's tried at 400MHz, then at 350MHz. Chips that don't operate at 350MHz are discarded. This process favours low clock speeds at the start of a chip's life but as production volumes and chip yields improve, the number of chips approved for higher clock speeds increases. Apple's problems, then, are not long-term ones, with working 500MHz parts due (albeit in low volumes) early next year once Motorola has fixed the 500MHz bug. IBM's entry into the G4 production business will help too, but that's unlikely to make any real impact until the second half of 2000 -- IBM has to go through the same ramp-up process itself. Still, that's little consolation for the many buyers who have ordered Power Macs at one clock speed and will now receive another. At this stage, it's not known whether only customers of the 500MHz will get reduced-speed machines, or whether the downgrade applies across the board. ®

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