I thought about Amdahl's Law a lot when I started Sauce Labs. To make browser test automation faster, the initial plan was to throw more hardware at the problem

I thought about Amdahl's Law a lot when I started Sauce Labs. To make browser test automation faster, the initial plan was to throw more hardware at the problem by getting more servers and running tests in parallel. But we were always looking for other things to optimize because we knew "throw more hardware at the problem" was going to stop working at some point. One example was virtual machine startup speed. In early days on EC2, Windows VMs took 10-ish minutes to boot up, I think part of the reason was because they had to do a disk image transfer first. But if you can keep lots of redundant copies of disk images in lots of places, you can reduce that waste of time on pre-boot network data transfer and ride the Amdahl's Law curve a little longer. Another trick is having the VM "pre-booted" by having a VM snapshot to jump to avoid the entire boot process. Of course, getting this much low-level control over the boot process to optimize for parallelability means building out your own cloud, which is another story for another day...