I am still _way_ behind on my perl6 e-mail but there has been a spate of discussion on gcc list about how garbage collector is bad for data-cache locality (particularly temporal locality).
At least some of gcc folk are considering a switch to refcounts to try and get gcc-3.* back to nearer gcc-2.* compile-speed. -- Nick Ing-Simmons http://www.ni-s.u-net.com/
