PPC 604 Powers Past Pentium: 4/18/94

IBM and Motorola have taken the wraps off their next processor, the 604, revealing the true performance potential of the PowerPC architecture. The chip, which the companies expect to ship in volume by the end of the year, is not only far faster than current Pentium processors but is likely to exceed the performance of all future Pentium chips as well. According to each company’s roadmap, Intel will not surpass the 604’s estimated 160 SPECint92 performance until the P6 generation—by which time PowerPC will have moved to even faster processors. Thus, the 604 will open a performance gap that Intel will find difficult to close. While the 604 bears some resemblance to its little sibling, the 603, most aspects of the design have been pumped up to improve performance. For example, the 604 can issue four instructions per cycle, twice as many as the 603, and includes an extra integer ALU. The 604 uses register renaming and out-of-order execution more extensively than the 603. Its on-chip caches are twice as large, weighing in at 16K for instructions and 16K for data. Pushing the clock rate to 100 MHz and beyond also lifts the 604’s performance. As usual, this added performance comes at a price. The die size of the 604 is more than twice that of the 603 and 20% larger than the P54C Pentium. Neither vendor has released pricing information for the new chip, but it appears that the 604 will not replace the 601, as originally planned. Rather, the 604 will be positioned above the new 100-MHz 601, offering significantly more performance than Intel’s Pentium for a similar price. The 604 will appear in PCs and workstations from IBM as well as in Apple’s second-generation Power Macs. The workstations will probably ship in 4Q94, with Macs and PCs shipping in 1Q95. Low-cost 604-based systems, running Apple’s Mac OS and IBM’s Workplace OS, will give the PowerPC boxes a performance advantage over Pentium PCs, but the 604 systems will be too expensive for most users, at least at first. PPC 604 Power