As far back as the late 1980s, chip pundits have predicted the demise of x86. Intel's CPU architecture was a dead end, they said, and the day was fast approaching when the chipmaker would reach the theoretical performance limit of CISC processor designs.
RISC CPUs were the future, they said. And sure enough, when the server market exploded in the 1990s, companies turned to RISC-based systems from the likes of IBM, Silicon Graphics, and Sun Microsystems to handle their heavy lifting.
Fast-forward to 2005, however, and an incredible turnabout has taken place. Not only does x86 still rule the desktop, but analysts now estimate that anywhere from 80 percent to 95 percent of all servers sold are based on the Intel architecture.
Meanwhile, RISC has fared far less favorably. Some designs, including DEC’s Alpha and Hewlett-Packard’s PA-RISC, have fallen by the wayside. Those still viable, such as IBM’s Power line and Sun’s Sparc, have been largely relegated to niche status as specialty chips for the high end. Even Apple, long a proponent of RISC chips on the desktop, has forsaken PowerPC in favor of Intel processors for its upcoming Macintosh designs.
The bottom line: You can’t escape x86. It’s everywhere, and the trend seems only to be accelerating.
So what happened? How could the pundits have been so wrong? And could we really be looking at the beginnings of an era dominated by a single processor architecture, one whose doom was first foretold almost two decades ago?
Intel architecture grows up
According to Nathan Brookwood, principal analyst at microprocessor consultancy Insight64, x86’s dominance is the result of a kind of perfect storm in the chip industry.
“No. 1, the computational performance of x86 processors has increased rather dramatically over the last 10 years,” Brookwood says. “No. 2, the software environments have gotten more robust.”
Brookwood says improvements include not just operating systems, but also application-level multiprocessing technologies such as Oracle RAC (Real Application Clusters).
At the chip level, one dramatic improvement has been the introduction of 64-bit addressing, which allows chips to access extremely large amounts of memory. AMD was first to market with 64-bit x86 chips, but Intel soon followed suit with its own EM64T (Extended Memory 64 Technology) architecture.
Dual core came next, with Intel now shipping dual-core Xeon chips to compete with AMD’s earlier dual-core Opterons. As opposed to clustering and grid technologies, which achieve mainframelike performance by linking banks of x86 servers, dual core brings true, RISC-style symmetric multiprocessing to the mainstream by building SMP directly onto the chip die. Similarly, vendors such as Dell and Sun have borrowed other engineering ideas from higher-end systems to build truly enterprise-ready x86 server hardware (see “Engineering sets x86 server products apart”).