There are plenty of known GC algorithms with arbitrarily bounded pause times. They do limit the speed at which the mutator threads can allocate, but per-frame allocations can be done the same way they are done in a non-GC'd environment (just allocate a pool and return everything to it at the end of each frame), and any allocations that are less frequent will likely be sufficiently rare for such algorithms.

I know people who have written games in common-lisp despite no implementations having anything near a low-latency GC. They do so by not using the allocator at all during the middle of levels (or using it with the GC disabled, then manually GCing during level-load times).