Classic Computer Magazine Archive COMPUTE! ISSUE 156 / SEPTEMBER 1993 / PAGE S7

Future upgrade options. (microcomputer processors) (Compute's Getting Stated With: Upgrading Your Processor)
by Richard O. Mann

As always with computer buying decisions, there's that nagging doubt about whether this is the right time to upgrade your PC. What if the prices go down tomorrow? (They will.) What if as soon as you buy a 486 upgrade, Pentium upgrades come out for only a little more money? (They won't - for a while.) What if the minute you buy a 66-MHz upgrade to your 486, a clock-tripled 99-MHz model comes out? (It might.)

We contacted the major chip makers and tapped into the industry grapevine to see what's likely to happen in the near future. Intel and its competitors are remarkably - and understandably - close-mouthed about their upcoming products. They worry that if you know what's coming out in the future, you might not buy what they're selling today. Nevertheless, we do have some information to share with you.

Pentium - Today's

State of the Art

As I write this, Pentium-technology chips have just made their way into the market in limited numbers. By the time you read it, they should be more common. At first, they're going primarily into network file servers, but, as the 486 did, they'll soon appear in stand-alone desktop units and eventually in laptops.

Many prognosticators predict that as soon as production ramps up and supply is adequate, the Pentium's penetration into the lower end of the market will go faster than the 486's penetration. Until Pentium-chip demand in new computers is met, however, don't expect to see OverDrive chips with Pentium technology for the upgrade market. They'll arrive sometime in 1994, according to Nancy Pressel, an Intel spokesperson.

The 486 chip was nearing the end of its third year before the OverDrive and other upgrade chips became common. The product cycle will go faster with the Pentium, now that upgrading is becoming a popular choice.

Trouble in Pentium


For over a year, 486 systems have been selling with an OverDrive socket specifically for a Pentium upgrade. Intel provided detailed specifications to the computer manufacturers, even though the Pentium was at the time still on the drawing boards. Buyers of those computers are in for two nasty surprises.

First, the chip that eventually will go into that socket isn't a full Pentium processor. It can't be, since Pentiums require a 64-bit external bus and 486 computers have a 32-bit bus. The hybrid chip is code-named P24T. Intel hasn't decided on a formal name for it yet - going from the X86 nomenclature will present new challenges in naming the many varieties of Pentium chips that will be forthcoming. (Pentium SX? Pentium DX2?)

Second, many - perhaps most, no one is sure - of these computers won't be able to run even the P24T chip, which will generate too much heat. Intel says it provided detailed specifications on the heat-dissipation requirements, but the manufacturers of the problem systems claim that the cooling requirements weren't adequately clear. Machines from major vendors (such as Dell) don't have the problem, but many computers made by second- and third-tier manufacturers may be unable to use the P24T

Intel says that it will come up with solutions so these computers can be upgraded. Some may need only additional fans or heat sinks. Others may require a whole new chip design that minimizes the heat problem - which may mean leaving out some of the advanced features that make Pentiums so desirable. It will certainly mean additional delays before the redesigned chips are available.

New 486 Upgrades

The 486 chip isn't at a dead end. It will continue to mutate into new varieties with higher speeds and other new features, such as lower voltages and improved power management features.

Intel plans to add its 486SL power-management technology to all its 486 chips in the immediate future, without raising the price.

Clock-tripled chips, which would take the 33 MHz chip to a full 99 MHz, are widely rumored to be in development, but the chip makers wouldn't confirm this. Nancy Pressel of Intel would only say that "clock-tripling is certainly a valid technique," and that, one way or another, "there will be higher frequency 486 chips."

Cyrix has just introduced its 486S chip running at 40 MHz or 50 MHz with System Management Mode (SMM) capabilities for better power management, in both 3.3 and 5 volt models. Unlike Cyrix's earlier 486-labeled chips, this one fits into a 486SX socket (the others worked only in 386 sockets) and has a 2K cache. The company's next 486 chip, code-named M7, is due to ship soon, perhaps by the time you read this. The M7 is the first Cyrix 486 that fits the 486DX socket and has a full 8K cache and a math coprocessor on board.

As you might expect, Cyrix has a Pentium-like superscalar processor in the works as well. However, the company makes no predictions as to when it'll be ready to ship. Code-named M1, it matches the Pentium in moving to two instructions per clock tick. Cyrix spokesperson Michael Bruzzone explains that the M1 differs from the Pentium in that it's completely backward compatible with all x86 software. The Pentium also runs earlier software, but requires the software to be recompiled in order to take advantage of the full speed of the processor. According to Bruzzone, the M1 is optimized for integer operations (while the Pentium is optimized for floating-point math), so it will run earlier software at full speed without recompilation.

The Next Step: P6

Intel admits that it's working on the next-generation chip, which is code-named P6. Beyond that, the company will say nothing. There's plenty of speculation around the industry, but it's merely speculation. Pentium has just arrived; Intel wants us to concentrate on its marvels before we begin looking beyond it to the next computational wonder.

The Micro 2000

In 1975, Gordon Moore, chairman and co-founder of intel, postulated what has become known as "Moore's Law," stating that each year, the number of transistors that can be put on a chip will double. Since then, his law has proven to be remarkably accurate.

Extrapolating into the future, Moore's Law predicts that individual CPU chips will carry as many as 100 million transistors by the end of the century. In comparison, today's state-of-the-art Pentium has 2.1 million transistors.

Intel has put together its official prediction of what the year 2000's microcomputer will be; it's called the Micro 2000. The current thinking on Micro 2000 is that it will run at 250 MHz and execute five instructions per clock tick.

Today's Pentium exceeds 100 million instructions per second (MIPS);the Micro 2000 should be capable of 2 billion instructions per second (BIPS). It also will have a gigabyte of memory and sell for prices comparable to today's 486.

And, of course, the end-of-the-century computers will still be fully backward-compatible, running all our old PC software. Any bets on whether we'll still be playing Tetris as the next century dawns?




Cache. A buffer where data is stored in a high-speed area of memory in anticipation of it being needed by the CPU. Cached data can be fed to the CPU at higher speed than would be possible if the data had to be retrieved from slower memory or storage. CPU output also can be cached.

Chip. A computer component that plugs into an internal socket to perform electronic functions. Generally used to refer to the CPU. Created from ultra-miniaturized silicon printed circuits, the latest CPU chip contains the equivalent of over 3.1 million transistors. See the listing of modern CPU chips in the article "What Upgrade Chips Are Available?"

Clock Doubler. A CPU chip that doubles the frequency at which internal CPU operations run. Also called an OverDrive chip.

CPU. Short for Central Processing Unit. This is the chip that does the actual brain work of the computer. See Chip.

Daughterboard. Any printed circuit board that is added to the computer in addition to the motherboard. Often used to refer to boards that upgrade oraugment the CPU functions.

Math coprocessor. A set of circuits designed to speed up the handling of floating-point math operations. Until the 486 series of chips, co-processors were separate, purchased at extra cost.

MHz. Short for MegaHertz. The frequency at which the system clock operates. The faster the clock speed, the faster the computer runs.

Motherboard. The main printed circuit board, which forms a permanent part of the computer. It generally contains the CPU and other necessary circuitry.

OverDrive. Intel's clock-doubler chip series. Also used to describe the built-in motherboard socket designed to hold these chips.

Pentium. Intel's latest CPU chip. (If Intel had continued its previous name numbering, this would have been the 586 chip.)

ZIF socket. A Zero Insertion Force socket that provides a built-in lever to ease the extraction and insertion of chips.