Will there ever be a need for a larger instruction set?

[Sarra]

Or, at least for the foreseeable future, is a 64 bit instruction set 'sufficient'?

 

This is mostly just idle curiosity, though having lived through the evolution of 8-bit to 16-bit, then on to 32-bit, and then (seemingly really rapidly), on to 64-bit, I'm really curious what the evolution will look like.

[Streetguru]

8 minutes ago, Sarra said:

 

I think it does more than just allow access to more memory, but we probably don't need it for a while yet, not sure how much something like Ryzen would even benefit from it.

[Sarra]

1 minute ago, Streetguru said:

I think it does more than just allow access to more memory, but we probably don't need it for a while yet, not sure how much something like Ryzen would even benefit from it.

It does more than just give registers for Memory capacity. I remember back in 1997 Cyrix had a 256-bit CPU; You ran 32-bit OS on it, and over time, it would 'convert' over to 256-bit, or something like that. I haven't seen or heard about it in such a long time, I can't honestly remember how it worked. We had a few of those CPU's and boards at the HS I went to, and I played with one for a little bit, but it wasn't any faster or slower than a regular old Pentium CPU, but I do think it was more efficient with power or something.

[Enderman]

Well, when the day comes that computers have more than 16 exabytes of memory then yeah we will need 128 bit.

It will probably be a while though.

[Sarra]

2 minutes ago, valdyrgramr said:

Will there ever be, well as technology evolves of course, but you can really only come up with theories as to when this will happen.  My guess is somewhere within the next one to two decades, but with some jumps in the tech world recently it's kinda hard to say.  Typically, larger instruction sets go to super computers first.   Mainly because of the cost of early development of the hw and sw.

No joking, I remember looking at Itanium CPU's, before AMD released the Athlon 64 and scrapped Intel's e64 architecture. Ironic, I actually came across an Itanium on ebay the other day.

[Streetguru]

3 minutes ago, valdyrgramr said:

I was thinking about 128 bit gaming, and then war flashbacks of the Atari Jaguar lady shouting kicked in.

 

Well, going back to your Cyrix comment the problem with them is they ran into legal issues due to basically stealing Intel's patents.   So, I think that was part of the problem there.   But, as mentioned by Enderman there's really no useful point to it at the moment.   I mean maybe for a data center.

It still gives you more bandwidth doesn't it? but x64 must still be fine on that at the current speed of DDR4/5.

[Enderman]

8 minutes ago, Streetguru said:

It still gives you more bandwidth doesn't it? but x64 must still be fine on that at the current speed of DDR4/5.

No it's not about bandwidth, 32 bit is 4GB of addressable memory, 64 bit is 16 exabytes.

Many computers these days have more than 4GB of ram, which is why everything is x64

We won't need x128 for a long time.

[SupaKomputa]

2^64 bytes = 18.44 exabytes

maybe 50 years later.

[igormp]

How do you define an X-bit arch? Is it due to the datapath or register sizes? Depending on your definition, current CPUs are 256-bit, or even 512-bit (see AVX-512).

 

Memory-wise, we don't even have 64-bit available. Current ARM and x86 CPUs use 48 bits for virtual addresses (~300TB).

 

The RISC-V spec also mentions a 128-bit subset, but irrc it's pretty vague since there's no much use for it currently.