Nicholas Carlini：现代棋引擎在1996年奔腾上可胜卡斯帕罗夫

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Could a modern chess engine on a Pentium have defeated Kasparov in 1996?

by Nicholas Carlini 2026-11-01

On February 10th, 1996, a computer program (IBM's Deep Blue) defeated the reigning chess champion (Garry Kasparov) in a game of chess for the first time. Deep Blue would go on to lose the match, but a year later, would get its revenge in a 3.5-2.5 rematch.

In order to achieve this feat, IBM spent several million dollars on research and development building a special-purpose computer specifically for this purpose. Deep Blue itself (the victorious, upgraded version) was powered by 30 P2SC processors each running at roughly 120 MHz, and (most importantly) 480 custom VLSI chess co-processors used to perform chess-specific operations like move generation and position evaluation. When it was built, Deep Blue was the 259th most powerful supercomputer in the world, and could analyze over 200 million chess positions per second.

But was Deep Blue necessary to beat Kasparov? Or could we have gotten away with an off-the-shelf 1996 desktop running a smarter chess engine?

As it turns out, we could easily have beaten Kasparov without building Deep Blue, using only commodity hardware, and it (almost certainly) wouldn't have even been close. I know this because, as I write this very sentence, I have sitting next to me a 200 MHz Intel Pentium Pro (released exactly 31 years ago---November 1st, 1995) with 64MB of RAM running a custom port of Stockfish that plays at an estimated Elo of 3300 ± 87 at classical time controls---far beyond the strength of any human, or indeed Kasparov's Elo of just under 2800. But wait, there's more! I've hooked this machine up to the internet with a Realtek RTL8139C Ethernet card, so you can play it below!

copy link Analyze on lichess

← All games

Connecting to the Pentium…

Resign

Other games in progress

Play vs. the Pentium

The Pentium Pro's monitor, live (its VGA text screen, refreshed every second)

wait, what?! how??

There are three ways to get stronger at chess: you can analyze more moves, analyze better moves, or analyze moves better. Famously, humans improve by doing the latter two: the average chess grandmaster during a classical game will analyze roughly the same number of moves as an amateur player, but they analyze only the most critical moves and do a better job with that analysis. Chess engines like Stockfish, running on silicon instead of our human brains, dominate us at the first of these and analyze millions of positions per second. And because there's not that much room for micro-optimizations on modern engines that will let a given CPU process more positions per second, most progress in chess AI also tends to follow how humans improve and finds better methods for selecting moves and analyzing boards.

Skill in chess is measured by an Elo score. A difference of 200 Elo means that you should expect the stronger player to win three out of every four games, and multiplicatively from there: a 400 Elo gap corresponds to a 90% expected score and a 1000 Elo gap gives a 99.7% expected score. The best chess engines that you could run on commodity 1996 hardware were rated roughly 2300 Elo. Deep Blue was rated 2700. In contrast, modern Stockfish is rated closer to 3700.

This raises the question: how much of the advantage of a modern chess engine comes down to the fact that a modern desktop computer is extremely fast, and how much of the advantage comes down to the fact that we've just gotten better at programming chess engines? As it turns out, the majority of the Elo gains (+720 of the +1335 gained) can be attributed to better programming, and not better hardware.

To test this, I ran two experiments. The first experiment uses Crafty, a competitive engine from 1996 whose source code is now available. On my Pentium Pro, the 1996 build of Crafty version 11.13 has an Elo of 1999 ± 90 at 1 second per move, and 2383 ± 77 at 10 seconds per move. On modern hardware (a Ryzen 7) this engine's Elo jumps massively to 2614 ± 97 at the same 1 second per move. But if I take this engine and slowly start to add all the knowledge we have about how to design better chess engines---adding modern search algorithms like fail-soft, LMR, correction history; adding better quiescence methods; and adding neural-net evals (NNUE)---then you can increase the Elo up to 2718 ± 34 on the Pentium Pro at 1 second per move, and 2974 ± 74 at 10 seconds per move.

In the second experiment I go somewhat further: instead of trying to update Crafty, let's just try to get Stockfish---the best chess engine today---running on 1996 hardware and see how it does. This takes some work and is mainly a matter of rewriting the code so that it uses 32-bit arithmetic (a PPro is a 32-bit machine) and doesn't use more than 64MB of RAM. This naive port has an Elo of roughly 2496 ± 64 at 1 second per move (2940 ± 76 at 10 seconds per move). But we can do better! A modern Stockfish engine is designed to run on a modern CPU. By making a number of adjustments to the algorithm and tuning it to the Pentium, we can increase its Elo to 2846 ± 35 at 1 second per move, 3109 ± 79 at 10 seconds per move, and 3180 ± 80 at 30 seconds per move.

The most concise way to summarize all of the above is just to have them play a match of 100 games against each other. And when I do this, I find that a modern chess engine running on a 1996 Pentium Pro wins 78, draws 17, and loses 5 games against the 1996 Crafty engine running on modern hardware.

The remainder of this article provides the details.

Technical details: Hardware & OS

There's not much to say about the hardware, to be honest. I bought a used ("vintage" said the listing; I feel old.) desktop PC with standard period-appropriate hardware. The desktop is running a 200 MHz Intel Pentium Pro connected to an Intel VS440FX motherboard with 64MB of SIMM RAM clocked at 66 MHz. The operating system boot off of a 1.44MB 3.5 inch floppy disk, and connect to the Internet via a Realtek RTL8139C. I also have a 1MB Trio64V+ graphics card connected over VGA to my monitor, with input coming from a PS/2 keyboard---but I don't much use either of those and instead communicate with it over a serial port connected to my modern desktop.

For those readers who may not be able to appropriately contextualize this hardware, a 200 MHz Pentium Pro sold for $1,325 at launch in November 1995, and four 16 MB SIMMs would have cost about $2,000. Add on the other peripherals, and this machine would likely have gone for about four or five thousand dollars. So it's a nice workstation, but by no means a supercomputer. However, given the rate of depreciation and the exponential rate of improvements to hardware, this same machine in 1997, when the second match occurred, would likely go for just a thousand dollars (because who would want to buy a Pentium Pro when the better-in-almost-every-way Pentium MMX was now available for just $400?)