30 Years Ago: Intel 386, 486 Chips Set the Stage for Windows Dominance

By Jeff Burt  |  Posted 2013-09-27 Print this article Print

These versions allowed Windows to become the dominant graphical PC operating platform around the world in the 1990s.

“Transforming from 16 [bit] to 32 bit would have been very important to Microsoft for the graphical interface,” Roger Kay, principal analyst with Endpoint Technologies Associates, told eWEEK.

Intel eventually released different versions of the chip, including the 386DX, which could work at 16- and 32-bit, and the lower-cost 16-bit 386SX. Two other versions were the low-power 386SL and the 386EX chips for embedded systems.

Intel eventually discontinued the 386 in 2007, though as late as last year, the chips were still being used, primarily in embedded systems.

The 486 also featured 8KB of Level 1 cache (it later was doubled to 16KB) and an integrated floating-point unit, which made the 486 less expensive and more efficient than its predecessors, which had to rely on a coprocessor for floating-point capabilities, according to Insight 64’s Brookwood.

The 486 reached a performance of 20 MIPS and—initially—speeds of 25MHz and 33MHz. It also offered some features, like pipelining, that had before only been used in mainframe systems. These features helped the 486 execute one instruction per cycle—as long as the data was already in the cache.

Like the 386, there were a number of versions of the 486 produced, including the 486DX, which had the integrated floating-point unit, and the 486SX, which didn’t.

The 486 represented a key turning point in Intel’s history. In a situation echoing Intel’s issues with developing the non-x86 Itanium platform for 64-bit server computing, the company in the late 1980s was working on two different and non-compatible 32-bit chips. In his book “Only the Paranoid Survive,” which was published in 1999, former Intel CEO Andy Grove talked about how the company, while developing the 486—which was based primarily on CISC (Complex Instruction Set Computing) technology and compatible with all PC software—also was working on the 32-bit i860 CPU, which was based on RISC. The i860 was fast, but not compatible with most software, Grove said.

In a passage in his book he outlined the problems facing Intel.

“We didn't know what to do,” Grove wrote. “So we introduced both, figuring we'd let the marketplace decide. However, things were not that simple. Supporting a microprocessor architecture with all the necessary computer-related products—software, sales, and technical support—takes enormous resources. Even a company like Intel had to strain to do an adequate job with just one architecture. And now we had two different and competing efforts, each demanding more and more internal resources.”

Internally, the company was conflicted—which project should get the resources? Which chip should be pitched to customers? And it caused confusion among system makers.

“The fight for resources and for marketing attention … led to internal debates that were fierce enough to tear apart our microprocessor organization,” Grove wrote. “Meanwhile, our equivocation caused our customers to wonder what Intel really stood for, the 486 or i860?”

Eventually, the market did decide, with vendors such as Compaq telling the company to stick with the x86-based 486 (though Microsoft fell into the i860 camp). Intel officials decided to stick with x86—as it did more than a decade later, when it followed AMD’s lead and brought 64-bit capabilities to its x86-based Xeon server chips.



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