Oh holy crap you're right—I have also had this "Xcode eats all the memory" bug, but it seems the fix detailed in that link has given me my processors back. Thanks!

Beta 1 you mean, released October 27?

Has anyone indeed started this discussion? I can't find one, and I would very much like to understand the justification behind this limitation.

.withUnsafeMutableBufferPointer doesn't work either, for reference.