However that's not something that is automatically solved by manual memory management. Using malloc/free on a desktop OS does also not provide a predictable runtime behavior, although unexpected pauses might be smaller than with most GCs.
The safest bet for predictable memory management and latency is the approach that is used by lots of embedded and realtime software: Don't allocate at all. Or at least don't do it in critical phases.
I think this is the point that is obscured when discussing "manual memory management" vs "GC" languages and just focusing on the behaviour/life-cycle of an individual allocation: the former generally provide tools and features that make easier/more natural to avoid allocations, whereas the latter makes the assumption that allocation is usually OK (which is, of course, a perfectly acceptable trade-off for the domains those languages target).
The safest bet for predictable memory management and latency is the approach that is used by lots of embedded and realtime software: Don't allocate at all. Or at least don't do it in critical phases.