For gaming, does RAM speed or capacity matter more once you have enough?

Yes. Once you’re at 32GB, speed (MHz) matters more than adding more capacity. 32GB is already more than most games need; going to 64GB won’t help frame rates, but faster RAM can bump them. Games are latency-sensitive, so faster RAM improves minimum FPS and smoothness—3200MHz vs 3600MHz might gain 5-10% in some titles. But don’t go crazy: past DDR4-3600 or DDR5-6000, diminishing returns kick in, and you still want good timings (CL16 or lower for DDR4, CL30-ish for DDR5).