IMO you can't automatically go from "we have a latency requirement" to "public cloud is out of the question". It depends on what latency requirement. If you can eat an intermittent delay of 20ms, AWS, to me still seems fine, you just need to plan ahead in terms of what resources you rent there. Between that, and the multiple seconds a GC pause could cost you, there is still a space where GC optimization on AWS would make sense. But if you're in HFT and target micro- or even nanosecond optimizations, you sure don't wanna run anything in that critical path on any public cloud.