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He also talks a lot about x86 having disadvantages as a CISC that are just wrong. He says: "If there are instructions that will never be used, why spend the si

by SirWart 18y ago

He also talks a lot about x86 having disadvantages as a CISC that are just wrong. He says: "If there are instructions that will never be used, why spend the silicon real estate to hard code them? CPUs optimized for OS X would be smaller, cheaper, and use less power than any Intel or AMD alternative simply because they could be simpler overall." The problem with this statement is that PowerPC is a RISC architecture, and it clearly was insufficient. Despite having tons of unnecessary instructions and backwards compatibility issues, x86 has huge economies of scale which is why very few people buy SPARC or PowerPC anymore. The core of an x86 is a RISC processor anyways, and the complex instructions get translated into micro-instructions for execution. The only way the x86 is going to be upset is from embedded processors or from massively parallel, but it's definitely not going to be from a processor "optimized for OS X", whatever that means.

boucher 18y ago
"The problem with this statement is that PowerPC is a RISC architecture, and it clearly was insufficient." PowerPC's shortcomings had nothing to do with being a RISC processor. After all, you said it yourself: x86 is really RISC at its core anyway. The "economies of scale" argument has nothing to do with the technical merits of the chip design, it has everything to do with the fact that every PC save PPC Macs has used an x86 chip for decades. Architecturally, x86 does have disadvantages. It's been designed over the years to maintain backwards compatibility -- meaning it's still living with mistakes that were made decades ago. There are a lot of reasons why its unlikely that Apple will start manufacturing custom chips to run OS X, but none of them are because x86 is a great chip design, or that it would be impossible to design a custom chip that would run OS X well.
- SirWart 18y ago
  The economies of scale comment was simply that back before the Pentium Pro, most people thought that RISC was going to take over since it is such a better system, but because Intel is able to sell so many chips it can afford to throw extra engineers at the problem and add things like out of order execution to the x86. Or rather there are much more important things than the ISA's technical merit when considering what is the best chip to use. Plus I don't think that Apple has a chance, or they will have anything to gain by making its own chips for desktops and laptops. The absurdity of "running OS X well is that OS X is not that special. If he means "running everything better" than it makes sense, because these are general purpose processors, and there is just a small set of instructions that are basically the same for all architectures. x86 is not the best ISA, but the Core 2 Duo is an excellent chip, and it's hard to make a better chip no matter what ISA you are using.

by SirWart 18y ago

boucher 18y ago

"The problem with this statement is that PowerPC is a RISC architecture, and it clearly was insufficient." PowerPC's shortcomings had nothing to do with being a RISC processor. After all, you said it yourself: x86 is really RISC at its core anyway. The "economies of scale" argument has nothing to do with the technical merits of the chip design, it has everything to do with the fact that every PC save PPC Macs has used an x86 chip for decades. Architecturally, x86 does have disadvantages. It's been designed over the years to maintain backwards compatibility -- meaning it's still living with mistakes that were made decades ago. There are a lot of reasons why its unlikely that Apple will start manufacturing custom chips to run OS X, but none of them are because x86 is a great chip design, or that it would be impossible to design a custom chip that would run OS X well.

SirWart 18y ago
The economies of scale comment was simply that back before the Pentium Pro, most people thought that RISC was going to take over since it is such a better system, but because Intel is able to sell so many chips it can afford to throw extra engineers at the problem and add things like out of order execution to the x86. Or rather there are much more important things than the ISA's technical merit when considering what is the best chip to use. Plus I don't think that Apple has a chance, or they will have anything to gain by making its own chips for desktops and laptops. The absurdity of "running OS X well is that OS X is not that special. If he means "running everything better" than it makes sense, because these are general purpose processors, and there is just a small set of instructions that are basically the same for all architectures. x86 is not the best ISA, but the Core 2 Duo is an excellent chip, and it's hard to make a better chip no matter what ISA you are using.