Just a little general information, what is the chips that are used in the Mac's?
Unlike windows computers and the old Mac's that use CISC (Compressed Instruction Set Computing) chips, todays current Macintoshes use RISC (Reduced Instruction Set Computing) chips. Hence we have the difference between the old CISC 680x0 Macintosh computers, the Quadra's, II's, LC's and early (three number) Performa's, and todays new Power Mac's, Performa's and clones. Today software is being written that is "Power Mac Native", so what's the difference?
CISC chips do one instruction at a time, each instruction one after the other. Each different instruction can be of a different length, and different instructions are written for different situations to shorten the time needed to do that particular computation. Each new instruction needs special handling by the chip, and adds to the number of transistors needed in the chip. There is a limit to how many transistors can be built onto one chip, and since speed gains on the chip also use up transistors, you eventually reach a maximum speed. Why do you think the fastest pentium chips have been sitting at 200MHz for a while?
RISC chips on the other hand use a smaller set of instructions (hence reduced instruction set computing), and also break each instruction into parts that are the same for each instruction. A common model is into five parts.
1)Fetch the instructions.
2)Work out what the instruction is.
3)Do the computation for the instruction.
4)Interact with the memory of the computer.
5)Finally give back the results of the computation.
The RISC chip is then designed to do each of these different instruction parts at the one time. Obviously the chip cannot do this for the one instruction as each part depends on the part before it.The RISC chip can though, do one of the parts from five different instructions at the same time. Hence the RISC chip is able to handle up to five instructions at once, so while RISC chips may need to do 3 instructions to do the same as 1 instruction for a CISC chip (CISC chips being designed with some nifty instructions) the RISC chip will still complete the instructions in the same time, and have done 2 others as well!
Hence a "Power Mac Native" application is written such that the RISC processor is able to do more then one instruction at a time, and therefore complete it's tasks faster.
The RISC chip uses less transistors in the chip for instructions, so more are available to use for speed, that's why you can get 300MHz Macs.
