Yes. At 4$/hr these instances are truly mind blowing.

BUT

With only 2TB of local storage, your 4TB dataset (or output set) has to pass over the net for every execution. At 10Gbs - this alone can take 20 minutes to 1hr.

If you want to write it to the local SSD - multiply that by x3 or x10 ?! ....

This 4TB of memory is still bounded by 4 x 30MB of L3 cache. Which means your single thread implementation will be slowed down by x3 or x5 due to memory latency.

Your multi core implementation will probably suffer even more.

Distributed system are VERY hard, but dealing with them is inevitable for certain workloads.