Consoles bitness: 8, 16, 32 or ?

[phoenixdownita]

I always thought that the bitness of a console was historically decided by the bitness of its CPU.

 

Examples:

NES -> 6502 derivative -> 8 bits

SMS -> Z80 -> 8 bits

SNES -> 65816 -> 16 bits

FM Towns Marty -> 386SX -> 32 bits

 

By the way I always thought that the bitness of the CPU had to do with the width of their data registers (Z80 and 6502 are 8 bit machines in terms of their most notable registers)

 

But then thanks to Motorola that kind of classified its 68K as a 16/32 just because things got messy.

 

The 68K has full 32bit data registers, the data bus is 16 bits, but then compare the 65816 [sNES] that has 16 bits registers but 8 bits data bus but it is still considered a 16bit CPU, not an 8/16.

The 386SX on the FM Towns Marty also is a 32 bits CPU with a 16 bits data bus but still considered 32 bits .... messy.

 

Even more the Motorola 68008 is a 32 bit CPU with an 8 bits data bus but no one would consider it an 8 bits CPU although sometimes is classified as 8/16/32-bit ... sure!

Motorola only uses the 32 bits full term from the 68020 on, so the Amiga CD32 thanks to its 68EC020 it's a full 32 bits console, but the CDI that uses a derivative of the 68K is not.

 

Remember that even in the world of PCs the first popular CPU was the 8088 which is a 16 bits (like its bigger borother the 8086) but with an 8 bits data bus and yet still considered a 16 bits.

 

Check this one:

http://en.wikipedia.org/wiki/16-bit#The_16.2F32-bit_Motorola_68000_and_Intel_386SX

 

With that in mind I believe it would be fair to classify 68K based machines as 32bits (at least 32bits capable) and that would cover Sega MegaDrive and NeoGeo and also bump the classification for the likes of the Commodore Amiga and the Atari ST.

 

By the same token keep in mind that the TI-99/4A is a 16 bits and so is the Intellivision.

While the TG16/PCE is an 8 bits due to using a derivative of the 6502.

 

What do you think? What decides the bitness of a console? Is the CPU class, the data bus or the VDP? The latter has rarely been used as a metric (PCE/TG16 tried), the former 2 (CPU / data bus) have been misused a lot (Jaguar 64 bits data bus comes to mind).

 

Also even if the CPU has a certain bitness the rest of its architecture can still cripple it, and a reduced data bus is crippling for sure (hence the 8/32 or 16/32 or 8/16 are not as high performance as they could be due to the choking at the data bus)

Edited April 27, 2015 by phoenixdownita

[The Usotsuki]

SNES has a 16-bit derivative of the 6502

 

It really can get hairy.

[7800fan]

Atari Jaguar can vary depending on which chip you make as master. It can be 16 bit system or 64 bit system. Or if you wrote a game that made use of all 5 chips, then it would be a "400" bit system.

[carlsson]

The question is if bitness matters anymore, or if it is better to talk about different generations. Then there comes consoles or computers that either were ahead of their time, which should put them in a later generation than when then were launched, or more commonly late arrivals to a former generation where the comparable competitors were out of the market long before the last addition.

[Bill Loguidice]

There is no right answer with this. I tend to prefer to defer to any system bottlenecks that might make a 32-bit system work in primarily 16-bit modes (meaning it's a 16-bit system), 64-bit system work in 32-bit modes (for instance, the Nintendo 64 was a 64-bit system, but the majority of games were 32-bit due to memory constraints), etc. In the infamous case of the Jaguar, while technically you're not wrong to say it's a 64-bit system, it really wasn't 64-bit throughout its architecture or how it was mostly used, so I personally don't think of it as a 64-bit system (but again, don't really care if someone else does).

[Bill Loguidice]

The question is if bitness matters anymore, or if it is better to talk about different generations. Then there comes consoles or computers that either were ahead of their time, which should put them in a later generation than when then were launched, or more commonly late arrivals to a former generation where the comparable competitors were out of the market long before the last addition.

 

Considering the grey areas, bitness doesn't really matter. I too agree that we should speak more in terms of contemporary systems and/or generations, which would give a better sense of overall technological capabilities.

[Cynicaster]

The bit designations of gaming systems are marketing constructs that have zero practical significance to the typical consumer.

 

And no, bragging rights for having more bits than the other guy does not constitute practical significance.

[Nebulon]

I think of the 68000 as a 32-bit CPU. I'm guessing the main reason is because AmigaDOS/WB is a 32-bit operating system.

 

That, and I was used to the half-width bus phenomenon right from the Intel 8088 days. To me, how the CPU speaks to the bus has little or no bearing on how many bits it is. When I think of a CPU and word length, I think of code.

[Lost Dragon]

For myself, the 'Bitness' has only been a small part of the overal 'power' of the system...

The Dreamcast it's claimed was 128 Bit where it was needed, yet i loved it for Sega's decision to not starve it of Ram, unlike the PS2 and thus we saw rich textures etc.

As a Megadrive owner, whilst the hardware's CPU gave it an edge over the PC engine and SNES in areas, i'd of liked more colours etc.

It's the classic swings and roundabouts situ.with marketing companies over the years doing some very selective claims which has often back fired.

Software counts more than on-paper performance.

[phoenixdownita]

I guess my point was diluted.

 

Assuming the bitness of the consoles comes from the bitness of the CPU, how does the bitness of the CPU gets computed?

 

I thought it had to do with the size of the data registers, but at least in the case of Motorola they thought it had also to do with the somewhat hidden size of their ALU and other internal circuitry.

On the 68K 32 bits instructions are slower than 16 bits counterparts due to said internal limitations, nonetheless the CPU exposes a 32 bits programming model, so it should be considered a 32 bits imho.

 

For a sec I thought that the external data bus size could have been used in the making of the statement that the 68K is a 16/32, as it was kind of implied when saying the 68008 is an 8/16/32 [whatever] but then that does not match the 65816 (8 bit data bus, 16 bit registers) as that has always been considered a 16 bit no 8/16 nonsense [yes I know it's the extension of the 6502 to 16 bits].

 

Hence the question, when you were reading the docs/ads of the time what did you think they referred to?

 

It's a fact that for the PCE their attempts at qualifying it as a 16 bits was from their VDP design and not the CPU, so that much is clear, but as an 8 bits it was something else.

Aside from the Jaguar where 64 bits is really only the data bus not the components interfaced to it [they could have made them that way, they simply didn't, 64 bits CPU at the time were extremely rare], the rest seems to match the data register size with the exception of the 68K based consoles (Intellivision and TI-99/4A are one off in that regard as they belong to the 8 bits gen but have 16 bits CPUs without much fanfare about it).

 

It is pretty obvious that as it comes to consoles from 3rd gen onwards they were mainly defined in jumps of the VDP (or GPU) technology more than anything else. It's been proven many times that even the fastest of the CPU cannot compensate for a crappy VDP (or GPU) no matter what. As the VDP (GPU) tech improved so did the CPUs and a new gen CPU ended up being paired with a new gen VDP (GPU) more often than not anyway.

 

I'm not against considering 68K consoles as belonging to the 16bits era (or 4th gen more appropriately), but not because of their CPUs bitness alone.

For example the Megadrive/Genesis although sporting a 68K is on the same league with the SNES which has a 65816 (16 bits), the NeoGeo I'm not entirely sure (likely its custom ASICs are all 16 bits) as it was well ahead of the pack and could be considered 32 bits, alas we tend to only use the 32 bits classification (5th gen) for the PS1 and the Saturn in which really the 3D was the most defining characteristic. If you take the 3D away I believe that a NeoGeo compares reasonably well with a Saturn or a PS1 offering. Keep in mind that 3DO, Amiga CD32, FM Towns Marty, NEC PC-FX are all considered 32 bits (5th gen) and yet no 3D for them.

 

The only real 16 bits CPU based "things" I recall are the PC-XTs (8088/8086) and the 286s, the rest of the computers of that time either were still 8 bits or 68K based (32 bits in my book).

I do not recall any 16 bits outside of the Intel based offerings (SNES being the only odd one out).

 

So in short where does the 16 bits gen came out from?

Sega seems to be the one with the big "16 bits" logo on their Megadrive/Genesis and it came out 2 years before the SNES.

Was it Sega marketing that single handedly created the whole bitness nonsense?

Edited April 27, 2015 by phoenixdownita

[Lost Dragon]

Regarding your last point (the tech stuff is'nt my area..at all)...Sega's marketing of the Megadrive/Genesis with the focus on the 16 Bit aspect over that of the 8 Bit NES did appear to be a key focus point, one which Sega were keen to hammer home and it worked bloody well.

 

 

Things sadly soon went south after that espically with Sega of Japan advertising the Saturn as a 64 Bit system due to twin RISC chips in it, but we'd already seen Atari attempt to play a similar trick Sega had with Jaguar being 64 Bit, it's rivals 'only 16 or 32 Bit' systems and that horrendous Do The Maths marketing angle.

 

So, i'd personally say it was Marketing..period that were to blame for the entire 'bitness' nonsense (a p*ssing contest, basically) along with other wars over nonsense like pixel animation speed, claimed polygon per second performance etc etc, none of which ever really bore any revelance to what the hardware could actually pull off in-game...

[The Usotsuki]

Neo Geo has the same pair of CPUs as the Genesis (68000+Z80) just clocked faster.

[Rybags]

 

[Rick Dangerous]

There is no need to discuss the Jaguar in this thread. If you do, exit thread "Do the Math" then return.

[carlsson]

I've read comments that both the Z80 and 6809 might be considered 16-bit processors, depending on which factors you use.

 

Furthermore, a system with multiple CPUs apparently should count all its bits together - just like Jaguar did although it left out some of the helper processors - which would make a Neo-Geo anything from 24 [16+8] to 40 [32+8] or even 48 [32+16] bit system. Likewise, a C128 should be at least 8+8 = 16 bit, and the same about an Apple ][ with Softcard (IIGS with a 65816 clearly is as much 16-bit as a SNES is).

 

But yes, it still is just a play with numbers.

Edited April 29, 2015 by carlsson

[Nutsy Doodleheimer]

https://m.youtube.com/watch?v=nxuna944dls

[Nebulon]

I've read comments that both the Z80 and 6809 might be considered 16-bit processors, depending on which factors you use.

 

Furthermore, a system with multiple CPUs apparently should count all its bits together - just like Jaguar did although it left out some of the helper processors - which would make a Neo-Geo anything from 24 [16+8] to 40 [32+8] or even 48 [32+16] bit system. Likewise, a C128 should be at least 8+8 = 16 bit, and the same about an Apple ][ with Softcard (IIGS with a 65816 clearly is as much 16-bit as a SNES is).

 

But yes, it still is just a play with numbers.

You're kidding about the adding bits together right?

 

I'm sure marketing firms would love it if it actually worked that way.

[carlsson]

If Atari were dead serious about the 64-bit Jaguar, everyone else should have the right to be as well. Also realize a PC with double CPU's, like a Pentium 3 MP or Athlon MP, easily becomes a 64 bit system. I'm not sure if those Quad-Core systems of today should be counted as 4 * 64 = 256 bits, but it would sound cool.

 

No, of course I'm just fooling around.

 

In the case of the Jaguar, I've read that many developers used the 68000 for the game logic and the two 32-bit GPU and DSP for graphics and sound. Now if you judge a system's overall bitness based on the main CPU used, the Jaguar in those cases would not only be degrated to a 32-bit system, for some people it'd be a 16-bit system depending on how they view the 68K. If nothing else, it kind of illustrates the problem and sillyness to sticking with the definition of bitness.

[high voltage]

[Nebulon]

Good article. The very last line just begins to talk about the PCs of the day and their ratio of CPU to graphics hardware. At that time, the CPU was relatively powerful compared to the video circuitry.

 

Today we're seeing the inverse situation. Now the GPUs are more powerful than the CPUs. Of course, no matter how great a video card you put into a modern 64-bit PC, it'll always be a 64-bit PC.

 

As for the Jag, the article does raise a pretty good point about games-specific processing. Indeed, if its main function is to push graphics around then maybe rating the machine by its general-purpose CPU is just not a fair description. The same sort of thing happened when a salesperson tried to explain the performance of the TG-16 when it was first released. Talking about it in terms of bits or MHz just didn't explain the (at that time) exceptionally good performance of the console.

[7800fan]

So about those double CPU? I used to own a dual quad-core Xeon CPU that with the right program it could be considered a 512 bits system (1024 bits if you figure in hyper-threading)

 

I am glad they dropped the bits after N64, it was pointless after a point. CPU hasn't made a good game system, only what the game program can do with the hardware.

[Torr]

CPU hasn't made a good game system, only what the game program can do with the hardware.

 

Ain't THAT the truth!

[CatPix]

You're kidding about the adding bits together right?

 

I'm sure marketing firms would love it if it actually worked that way.

 

Do the maths

 

And just a correction : the 3DO is very capable of 3D, with games such as Need for Speed being visually close on PS1 and 3DO.

[carlsson]

Huh, that was a disturbing adverisment.

[Lost Dragon]

From:Playstation/N64 Beater Unveiled At VM Labs news article (EDGE):

(Richard) ....Miller strenuously denied speculation that Project X is a 64Bit System. "The arguement that more bits are better does'nt hold water" he says, "This does'nt mean we don't have more bits-we do.But it's a crazy game to get into-we got into that situation with the Jaguar and it was terrible"