I'm not sure what to think about this G5 thing...

[Catfish_Man]

Take a look...

...at IBM's PPC roadmap. The next processor on the list is dual core, 1GHz+, integrated SIMD engine (sounds like Altivec to me), .13 micron. The one and only place that might clash with our current info about the G5 is that it doesn't say whether it's 64 bit or not. We've been assuming that the G5 will be the Motorola 8500. It might not be.

P.S. Think about this: Assume that the G5 (the IBM one) gets the same amount done per clock pulse as the G4 (longer pipeline, but faster bus and smaller wires). Assume that the rumors we've heard about its clock frequency are correct (1.6GHz top). That would mean that ONE core of the dual core chip would be twice as fast as the current 800MHz G4. Since it's a dual core chip it would be close to 4 times as fast. If you had a dual processor version of it, it would be getting somewhere near 8 times as fast. Somehow I doubt they're going to release a DP version of it first, but it's fun to think about

 

[KingArthur]

Sorry to keep reverting back to this data-rate thing, but since anshelm mentioned arstechnica, I couldn't help myself. Now, since you have read the articles, you would have read that the ALU IS AT DOUBLE THE CORE FREQUENCY!! I read it twice in the last two days. Frequency is measured in hertz (cycles/unit of time) and bandwidth is measured in bits/cycle (Mbps). The P4 has two double speed ALUs which in theory would do the job of four regular ALUs; but we all know that unless you keep the ALU fed with data, it has less of an effective speed. The P4 also has a third ALU for complex operations like multiplication and division which runs at core frequency and usually takes anywhere from 15-45 cycles to complete.


Hey Swatara; I am really getting into the archetectural designs of CPUs and was wondering if you would know of any really good sources of info on CPUs (not just G4 and P4, but also any AMD processors and ones like the G3 and P3 and P2 (aka celeron)). Give me an e-mail if you would be so kind.

 

[KingArthur]

Oops. I forgot to reply to your response Catfish_man.

I believe that if we are correct in judgements of this being the correct processor, then yes, the SIMD would be AltiVec (or another name). We may even see a newer SIMD that integrates not only into Vector processing but into FlotingPoints and/or other various elements. This would definately be an advantage and innovation which would stun the market. It would be quite hard to program for a SIMD FPU, though, because of all the conditionals needed to be processed.

 

[Catfish_Man]

I think...

Originally posted by KingArthur
Oops. I forgot to reply to your response Catfish_man.

I believe that if we are correct in judgements of this being the correct processor, then yes, the SIMD would be AltiVec (or another name). We may even see a newer SIMD that integrates not only into Vector processing but into FlotingPoints and/or other various elements. This would definately be an advantage and innovation which would stun the market. It would be quite hard to program for a SIMD FPU, though, because of all the conditionals needed to be processed.

...that you're misunderstanding vector processing a bit. A vector is a group of floating point or integer variables. Altivec can do either floating point or integer math, but only on multiple variables at the same time. Most of the info on processors that I have is from http://www.arstechnica.com . I know that's where the G4 v P4 article is, but they have some on the Athlon and Itanium procs too.