Virtualization and Processor Capability

In the old days[1]  the big computer companies competed fiercely on processor performance: a few extra megahertz here & there could make the difference between winning that multimillion dollar sale & being relegated to the also-rans.  Applications and operating systems were monolithic, giant chunks of code that consumed vast quantities of the CPU's processing time, so the faster you could  run through that single-threaded code, the better.

These days, the "processor wars" are done & dusted. There's really nothing that the relatively low-volume-and-hence-high-price RISC processors found in the big UNIX systems from Sun, HP & IBM can do that the relatively high-volume-hence-low-price x86-64 processors can't. So unless you're looking for a specific niche solution (from Snoracle[2]) or especially clever I/O virtualisation (IBM Power), there's really not much reason to be putting your workloads on anything other than an x86-64  system.

In fact, processing capacity is so grotesquely huge these days (and has been for a while) that we chop that capacity up into little units & assign them to many operating systems at the same time. This is called "virtualisation" (stop me if I'm going too fast).   This leads to the question of whether we can get away with even less. Certainly in the dim dark ages of last century, we were able to run multiple web servers on a single cpu systems; even given the additional complexity of some web apps these days, there are many applications that don't warrant the full power possible even with virtualised x64, and certainly not the power & cooling requirements of those larger servers.

This is why people are interested in ARM and Atom processors - lower performance than the high-end x86-64, but with sufficient capacity to do the job, and much more attractive characteristics for power, cooling & price.

So the future of server selection could be much more about power consumption (& cooling costs) over its lifetime than raw performance.  In fact, it's almost certain.

1: Old days, for purposes of this article, are before about 2006. Bleh. I feel old.

2: Snoracle. Sun + Oracle. Also, possibly onomatopoeia .