>> It puzzles me how this is possible.
>>
>> Sure, the Xeon probably has a much bigger cache and a slightly faster
>> bus to the RAM chips. But is that *all* that makes it faster? Or is
>> there more to it than that? I have no idea.
>
> The Pentium 4 line is notorious ineffecient in it's use of the clock
> cycles, and each of it's generations just got worst of than the previous
> one.

Isn't this roughly the timeframe when AMD, Cyrix and half a dozen others 
suddenly popped up with compatible chips running at the same clock speed 
yet delivering massively increased performance, and Intel were all like 
"oh crap!"?

> The problem was coined to an excessively long instruction pipe,
> that got longer with each sub versions. It topped at over 200 steps...
> It also greatly increased it's power requirments.
>
> With the new core2, they chopped that down around 30~40 steps with the
> performance boost, and power consumption decrease, we can now experiment.

Why would you build something that's vastly harder to design yet 
delivers awful performance? That doesn't make any sense. (I also don't 
see how it's *possible* to have a 200-step instruction pipeline, unless 
you were deliberately trying to be silly.)

> A Xeon system use a more advanced I/O architecture and beter memory
> management. It's instruction pipe is relatively short. It probably have
> beter cache management as well as larger cache, both L1 and L2. It's L1
> cache is probably distinct to the L2 cache, while the pentiums L1 cache
> address space was included in the L2 address space.

Can we really attribute all the performance advantages of 10 years of 
R&D to a bigger cache and an on-board SDRAM controller?

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