Microbytes / December 1992

Intel Introduces Speedier 486SX
and OverDrive Chips

Tom R. Halfhill

Intel has upped the ante again, introducing in September its fastest 486SX microprocessor and a new speed-doubling OverDrive chip. The new CPUs will accelerate the trend away from 386-based systems and put more pressure on Intel's competitors, who have yet to market a full-fledged 486-compatible processor.

The new 486SX is clocked at 33 MHz and is rated at 27 MIPS. That's about twice as fast as a 33-MHz 386DX. Until now, the fastest 486SX was the 25-MHz version, which delivers 20 MIPS. Intel also makes 16- and 20-MHz versions of the 486SX.

Unlike the 486DX series, the 486SX chips lack an FPU. Intel's OverDrive chips are designed to provide an upgrade path for 486SX systems. When plugged into a special socket on the motherboard, an OverDrive chip disables the 486SX and becomes the new CPU. The OverDrive is functionally equivalent to a 486DX with an FPU, but it runs twice as fast internally as the 486SX it replaces and communicates with external devices over the CPU bus at only half the OverDrive's clock rate. The OverDrive chip announced as a companion for the 486SX/33 is clocked at 66 MHz and improves performance by about 70 percent.

More than a dozen manufacturers joined Intel's introduction with announcements of new 486SX/33 boards and systems. Among them are AST, Apricot, Asustek, Elitegroup, Epson, First International, Gateway 2000, Gecco, Juko, NCR, Olivetti, Tandy, and Zeos. System prices range from $1600 to $2200.

Intel's list price for the 486SX/33 is $189 in 1000-unit quantities. That compares to $109 for the 486SX/25 and $94 for the 16- and 20-MHz versions of the 486SX.

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