Re: When you say spare cycles...
With tasks accessing the memory in a more or less random way, disabling paging/swapping makes a lot of sense. Once any non-trivial amount of memory gets paged in and out (all the time), your cores are mostly idle, waiting for memory pages (thrashing). I have seen slowdowns by a factor of more than 1000, the computer basically doing nothing but testing how many operations the disk will survive.
Dedicated "out of core" algorithms exist for certain tasks (e.g, for FFTs) but unless the documentation says they have that feature it is better to assume that it absent.
Biting the hand that feeds IT
