I am trying to develop a computing application which needs a lot of memory (>500gb). Buying a single machine for that is overly expensive. I can, though, buy ~100 small instances on Digital Ocean or similar, divide the memory in blocks and use TCP to emulate shared memory between the instances.

Now, my question is: how can I measure/predict the time it will take for two processes in two different machines like that to share information, in comparison to IPC and shared memory? Are there rules of thumb? I don't want exact values, but knowing more or less how much faster one is would be very helpful in visualising the feasibility of this approach.