Yes, it's a Parrot thing.

It's possible that something like a generational GC can "cycle" slowly enough that the pages to be swapped in can be controlled and even anticipated. Also, a compacting GC will potentially run in a smaller footprint than Perl 5. (Though I think it was decided recently that a compacting GC was incompatible with threading in Parrot, if I recall.)

But I agree with Abigail. If you're running a server, real memory almost always outperforms virtual memory. And with 64-bit computing coming online, there's really no limit to the amount of memory you can add now, apart from arbitrary limitations of particular hardware architectures that chintz out on giving you all your address lines...