one would go back to early x86 CPUs and strip all the SIMD extensions
I don't think I understand. This seems to contradict the inclusion of Altivec and further enhancement with VMX128 in Xenon as well as the very nature of the SPEs in Cell.
No? Intel is introducing an octo-core. Or did you mean the different types of cores i.e. PPE, SPE, GPU pixel shaders, GPU vertex shaders? Or... just the sheer size that eight main cores implies on the manufacturing side?I don't think anyone will go as multicore as Sony did with PS3. 4 cores seems to be a safe bet.
But on another note, how threaded could a game get? Just looking at the Killzone 2 slides on deferred shading, they mention SPU usage as follows:
- Display list generation
- Main display list
- Lights and Shadow Maps
- Forward rendering
- Scene graph traversal / visibility culling
- Skinning
- Triangle trimming
- IBL generation
- Particles
I imagine that at some point, the typical game won't be threaded so much that each thread is even using up a significant amount of CPU time. Thus there isn't a need to have infinity billion cores. On PC the analogy is the hundreds of threads that might exist, but only a select few actually take up measurable processing time.
I suppose that's the idea behind simultaneous multi-threading or "hyper-threading", which I think we'll still see in the future for consoles as a way to "cheaply" extend the number of threads that may be handled.
I'm still wondering if MS will ask IBM to design something "like" an SPE or go with the full-on multiple cores as Intel or AMD are doing. At 45nm, an eight-symmetric-core chip is going to be huge. Perhaps MS will do another weirdo setup and go with 5 cores with SMT capability, and hopefully with a lot more L2 cache!
Would that really be worth spending transistors (since we're already talking about customizing an x86 core)?At the same time I believe consoles would benefit from some of the virtualization technologies of modern x86 CPUs. Back-compat would be a little bit easier (and safer).
I'm still not convinced in any way they'll go with an x86 design, let alone a custom-designed one. AMD doesn't seem to have the resources to do a custom design that wouldn't see use in the PC space. And the same reasons for not going with Intel for the 360 probably aren't going to be resolved.
At the very least, they can skip out on VT by extending the Waternoose design.