Linked by Nicholas Blachford on Wed 9th Jul 2003 16:43 UTC
Talk, Rumors, X Versus Y This article started life when I was asked to write a comparison of x86 and PowerPC CPUs for work. We produce PowerPC based systems and are often asked why we use PowerPC CPUs instead of x86 so a comparison is rather useful. While I have had an interest in CPUs for quite some time but I have never explored this issue in any detail so writing the document proved an interesting exercise. I thought my conclusions would be of interest to OSNews readers so I've done more research and written this new, rather more detailed article. This article is concerned with the technical differences between the families not the market differences.
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Code Density
by GloomY on Sat 19th Jul 2003 12:22 UTC

I would like to carry on the argument of Anton Klotz in comment 56, that x86 has better code density due to inconsistent length of instructions. Of course this makes instruction decoding more difficult, but this yields some other advantages for x86 which have not been mentioned by Nicolas:
At first memory bandwidth required for instruction fetch from main memory is reduced (Anton Klotz pointed that out). Secondly the hitrate for the L1 instruction cache and L2 cache with both the same size is noticeably higher for x86, because of the greater code density. Thus, performance for RISC architectures is lower due to more cache misses when fetching instructions. This means that RISC processors need larger caches to acchieve the same hitrate when execution the same (!) type of application as x86. As everybody knows, caches eat up an enormous amount of transistors on the die. Therefore Nicolas' argument that you can save die space due to less complex decode circuits is simply ridiculous. The high code density of x86 is one of the greatest advantages of that architecure and not a weakness.

What I'm missing here is a fair consideration of both architectures. Only counting the advantages of RISC and the disadvantages of CISC is not what I call a good article...