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It's getting to the point where nobody wants a notebook computer unless it has a 486 microprocessor inside. The magic 486 moniker implies fast processing speeds and leading-edge technology. However, those three digits alone don't ensure a consistent level of performance.
Even among just the Intel offerings, 80486 CPUs come in a variety of flavors and clock speeds--from 66-MHz DX2s down to 16-MHz SX models. Meanwhile, rival silicon manufacturers, such as Cyrix Corp., are also using the 486 designation.
So just what can you expect when you buy a 486 notebook?
To help sort out the confusion, we've tested 12 25-MHz 486 notebooks from established and lesser known vendors: ALR Ranger M4/25s, Altima 425, Aspen (formerly Aquiline) Personal 486, Grid 1755/486SLC, Keydata Keynote 486SLC/25, Micro Express NB486SLC/25, Northgate ZXPortable, PC Brand LeaderBook 486SLC/25, Texas Instruments TravelMate WinSLC, Texas Instruments TravelMate 4000 WinSX/25, Toshiba T4400SX, and Twinhead Slimnote 4SX/25. Six of the systems are powered by Intel's 486SX/25, five by Cyrix's 486SLC/25, and one by Texas Instruments' 486SLC/25.
These machines comprise the meat of the high-performance notebook market. More reasonably priced than top-of-the-line 486DX systems, they still outperform 386-based competitors. There are some major differences between the microprocessors, however.
In our tests, notebooks incorporating Intel's 486SX/25 clearly outperformed the Cyrix-based machines. The Intel units dominated the top of the SYSmark92 ratings, while the Cyrix entries straggled in near the bottom. In fact, the fastest 486SLC/25 notebook--PC Brand--was almost 36 percent slower than the fastest 486SX/25 system, the Texas Instruments TravelMate 4000 WinSX. This system performed almost twice as fast as the Grid 1755, which was the slowest SLC notebook. Even for two identical machines, except for the processor--TI's TravelMate WinSLC posted a SYSmark92 close to 38 percent slower than its 486SX/25 sibling.
Intel's dominance in these speed tests isn't surprising; the Cyrix and Intel chips come to their 486 designations from opposite directions. The Intel 486SX processor is essentially a crippled version of the full-powered 486DX. Unlike the 386 line, in which the SX version used a 16-bit external path, Intel created the 486SX by simply disconnecting the 486DX's math coprocessor. The 486SX shares the DX's full 32-bit data path and 8K cache.
The Cyrix 486SLC, on the other hand, is really a hybrid of...