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A number of bits is often used to qualify some video game consoles: Master System and NES/Famicon are 8 bits systems, Megadrive/Genesis is a 16 bits system, etc.
What do this number actually represent for those different hardwares?

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closed as off-topic by Josh Jan 6 '16 at 16:19

  • This question does not appear to be about game development within the scope defined in the help center.
If this question can be reworded to fit the rules in the help center, please edit the question.

  • \$\begingroup\$ What do you know about your OS being for 32 or for 64? If you understand what does that mean, the same applies for consoles. Consoles have processor architectures with even more bits: GameCube has 128bits (doubling the amount of bits in modern pcs, squaring the ALU and addressing capacities than modern pcs) \$\endgroup\$ – Luis Masuelli Jan 6 '16 at 15:23
  • \$\begingroup\$ I'm voting to close this question as off-topic because it isn't about making a game, but rather industry trivia. It may be on-topic at Arqade. \$\endgroup\$ – Josh Jan 6 '16 at 16:19
  • \$\begingroup\$ In fact, similar questions have already been asked over there. \$\endgroup\$ – Josh Jan 6 '16 at 16:21
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    \$\begingroup\$ @JoshPetrie I'm unofficially voting to reopen this question. This seems like something game developers should know. \$\endgroup\$ – Evorlor Jan 7 '16 at 5:22
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It usually refers to the CPU architecture. Grossly oversimplified the bit-size of a CPU, is the size of numbers it can perform calculations with in one operation. An 8bit CPU can work with numbers up to 256, a 16bit CPU with numbers up to 65536 and a 32bit CPU with numbers up to 4294967296. Any of these CPUs can still be used to make calculations with larger numbers, but it needs multiple operations to do so.

The third generation of home game consoles was very obviously an era of pure 8-bit systems. The market-leader of that generation was the NES, the runner-ups were the Sega Master System and the Atari 7800. All systems used 8bit architectures through and through.

The fourth generation, commonly called the 16-bit generation, is a bit fuzzy. The two dominant systems were the Sega Mega Drive (aka. Genesis for North-America) and the SNES. Both systems were marketed as 16-bit systems. But the Motorola 68000 CPU of the Sega Mega Drive was technically a 32-bit CPU, even though it communicated through a bus which was only 16bit wide. Now you could say "duh, so it's the bus size which counts". But the Ricoh 5A22 16bit CPU used by the SNES only had an 8bit data-bus. So whatever technical definition you use, either the Mega Drive is a 32bit system or the SNES is an 8bit system.

In the fifth generation, the three competing systems were the Sony Play Station (32bit CPU), the Sega Saturn (two 32bit CPUs which SEGA marketing sometimes added up to 64bit which is technically quite nonsensical) and the Nintendo 64 (64bit CPU). This is the generation where counting bits stopped making sense because not even the marketing departments of the different companies agreed anymore in which generation they were in.

Generally speaking, the number of bits of a CPU can be compared to the number of cylinders of a car. More is usually better, but it alone is not a meaningful number to compare how powerful different models are.

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To give a few more details, a higher bit architecture primarily allows for more memory to be used. It also allows for higher precision data to be included. However, it's been a bit of a misnomer, it was generally accepted that higher bit systems were better (And that holds true to a degree), but it was often used when it was not the case. For instance, according to the 6th generation gaming console Wikipedia page, that generation was referred to as the "128 bit" generation. However, the major consoles actually used:

  • X-box- 32 bit.
  • Game Cube- 32/64 bit.
  • Playstation 2- 64 bit (With a "fudge" factor, allowing for 128 bit vectors)

It is worth noting that there is a huge difference from an 8 bit to 16 bit, and 16 to 32 bit. There is a smaller difference from 32 to 64 bit. Beyond there, there isn't many practical advantages for daily application. This is mentioned in the same article listed above. Here are a few practical limits of the various bit sizes:

  • 8 bit- This severely limits the colors, to only 255. It also limits the complexity of instructions that can be done.
  • 16 bit- Allows for much more color, still not quite allowing true color, but looks more realistic. Allows for more complex instructions. Still doesn't really have enough to do true 3d processing, but is otherwise adequate for most purposes.
  • 32 bit- The only real limitation is the ram, which is limited to 4 Gb. This wasn't a significant factor until about 2010. Allows sufficient processing power to manage 3-d systems. 32 bit allows for "true" color as well, which usually uses 8 bits for each color, plus 8 bits for the alpha chanel.
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    \$\begingroup\$ Note that most CPUs can process higher values than their bit-ness, they're just slower at that. The main limiting factor is usually not the number of colors per pixel, but rather the total amount of memory that can be used for storing these pixels (and any other game/program data). Reducing the number of (simultaneous) colors by using a color palette is just a workaround to be able to store an entire frame in memory. \$\endgroup\$ – uliwitness Jan 6 '16 at 17:44
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The number of bits here, represent the CPU architecture.

A 32-bit gaming console, utilizes a 32-bit Central Processing Unit.

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  • \$\begingroup\$ While this is the generally accepted explanation, it is technically not entirely accurate. The Sega Mega Drive was commonly called a 16-bit generation system (even by SEGA marketing), even though it used the Motorola 68000 CPU which was technically a 32bit CPU (but with a 16bit external bus). \$\endgroup\$ – Philipp Jan 6 '16 at 15:35

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