Interesting that the one has such large capacitors in it. I imagine that is as last-ditch effort to keep the board powered long enough to finish flushing all of its caches in the event of a power failure.

That’s exactly the point of power loss protection (aka PLP.) As a side effect of not needing to wait for a flush after a write synchronous write workloads are dramatically faster on enterprise drives with PLP.

Edit: To add a bit of detail - you don’t need to wait for a flush after a synchronous write with PLP because the drive firmware can lie and immediately return from a flush call because there’s enough backup power to complete that flush if the power were cut.