> How much bigger does the core interpreter + built-in extension modules get when you make this change? How much more memory is used by real world programs?

Well, any optimization is a matter of trade-off between memory and CPU. Last years, CPU are not really getting way faster (especially when you consider that Python is usually only able to use a single CPU thread), whereas computers are getting more and more RAM.


> It should be tested on a number of systems too; any losses to cache unfriendliness would be highly dependent on the size of the CPU cache.

I prefer to no pay too much attention to assumptions on the hardware. I prefer to only trust benchmarks :-)