I don't think this is a problem; you can usually turn off the GC during time-critical code, and in most cases, such code is in C anyway (handled via a foreign function interface), and at least in normal use, you're in control at that level. Besides, modern hardware is far faster than people seem to realize, and modern GC's don't spend much time on a sweep. Gad, now I'll have to go and run some tests...