I don't think he means arbitrary precision, I think he means fixed point.

And to answer him: Some programs can use it, some can't. IMO every program that can should, not not all do.

Top500 machine CPUs are usually your standard Intel or AMD CPUs[1].

In the current top 10, 5 are Intel, 4 are AMD (and 1 SPARC64). Many have Nvidia GPU co-processors.

The only slightly exotic architecture in the top 10 is number 10, which supplements its AMD CPUs with Cell co-processors.

[1]http://en.wikipedia.org/wiki/TOP500#November_2011