The 25 greatest PCs of all time

13. IBM Personal Computer/AT Model 5170 (1984)

Three years after IBM's first PC shipped, the PC/AT marked both a revolution and an evolution in personal computing. The revolution came in the form of powerful specs; the evolution came in the system's design refinements (no, we're not talking about its honking big beige box). It was another IBM hit, although it also turned out to be the last IBM model to serve as a standards bearer for the entire PC industry--a year later, Compaq's Deskpro 386 ended IBM's stranglehold on PC innovation.

The PC/AT was the first system to use Intel's 80286 CPU (first a 6-MHz model and later an 8-MHz model). It also featured a 20MB (or greater) hard disk that was faster than, and had double the capacity of, the PC XT's original hard drive, supported both 8-bit and 16-bit expansion cards, used IBM PC-DOS 3.0, which supported high-density 1.2MB (5.25-inch) floppy disks and even integrated a battery on the motherboard to power a real-time clock. Its keyboard, meanwhile, introduced the basic layout we still use today, including a number pad (with cursor keys and a key lock) and dedicated function keys. And the system could handle advanced graphics with its optional 16-colour Enhanced Graphics Adapter (EGA) or 256-colour Professional Graphics Controller (PGC).

Like many PC model designations, AT stood for something--and no, it had nothing to do with the Imperial AT-AT walkers featured in The Empire Strikes Back. The term was short for Advanced Technology.

12. MITS Altair 8800 (1975)

Computer historians are still squabbling over whether MITS's Altair was the first true personal computer. (Earlier candidates include the Kenbak-1 and Micral-N). What's undeniable is that it was "the first machine to really capture the imagination of the geek sector in a big way", says Erik Klein of Vintage-Computer.com. "The fact that other companies quickly jumped onto the bandwagon was proof of its power and allure."

The Altair started life as a build-it-yourself kit--little more than a box, a board, an Intel 8080 CPU (which MITS bought at a discount because of cosmetic blemishes) and 256 bytes of RAM. At first, you needed to program it by flipping switches, until Bill Gates and Paul Allen started a tiny company called Micro-soft (yes, with a hyphen) and came up with a version of the BASIC programming language that would work on the system.

Software from Bill Gates wasn't the only thing the Altair had in common with today's systems. Much of the infrastructure that would support later PCs--from disk-drive manufacturers to software developers to computer stores--sprung up to support it. There were even clones, such as the popular IMSAI 8080.

The Altair's time as the dominant computing platform was brief and, in 1978, it was discontinued altogether. But what a legacy it left.

11. Sony VAIO 505GX (1998)

In late 1997, Sony introduced the VAIO PCG-505 in Japan, proving not only that thin was in, but that being thin no longer meant compromising on computing power. The PCG-505 measured just 0.94 inches thick--amazingly slim for the time--and weighed a mere 3 pounds (the chassis was made of magnesium alloy). And, when this notebook first hit the United States in the latter half of 1998 as the Sony VAIO 505GX, it spurred an ultra portable revolution.

But, the 505GX didn't come cheap, although it packed in a fair amount of functionality for a compact notebook PC, including a roomy, comfy 10-inch-wide keyboard (1 inch wider than the keyboards of competing sub-notebooks of its time). The 505GX improved on the Japan-only version with specs that included a Pentium MMX-266 CPU and a 56-kbps modem. In our tests at the time, the notebook's lithium ion battery lasted 4.7 hours, which we deemed "an adequate figure but hardly stellar.".
Sony continued the 505 line with later iterations such as the X505; its current ultra portables, such as the TX line, retain some of the 505's design flair.