CompuServe Messages

> Although RISC cpu's are "faster", people are over looking that a > CISC cpu takes less CODE than a RISC cpu with software doing > the missing instructions. You seem to missunderstand the basic differences between CISC and RISC. A CISC CPU brings in complex instructions and _interprets_ them using micro-code. Most instructions requires a micro-code routine to be run. RISC says "Why can't that micro-code be my actual machine code?". This cuts a _lot_ of overhead out of the CPU. I spent three years of my recent life _very_ deep in the microcode internals of several large computers and I belive I have very good grounds to stand on. Dollar for dollar, executing the same source code, a RISC machine will almost always walk all over a CISC machine. i.e. a 66Mhz PowerPC601 chip is only $20 more than a 50Mhz 68060 yet is lots faster. And RISC chips are usually much easier to scale to very high clocks and effective speeds. You are 100% correct about OS efficiency. But, please don't forget that same efficient OS could be modifed to run on a RISC machine. The OS and the CPU are two different issues! Of course an good OS can make a poor CPU look okay, and a pig OS can saddle a RISC CPU. But all things being equal, a RISC computer will eat a CISC alive! RISC _is_ the future for at least the rest of this decade until something better comes along. (Which it will!) I can only hope that the OS's don't become pigs. —– Andrew