Upgrading on-board components on hard drive controller boards?

I was recently looking at some hard drives to replace one that had gone bad and I was amazed at some of the stats on the new units. I was looking at 4TB models and they had caches from 32Mb to 256 and most surprisingly of all the 32MB was the high end "Enterprise Datacenter Gold Edition SAS"! As compared to some much "lesser" performing drives of lower cost and at least 2x the cache. This drive was the only one with 32MB of cache, even their least expensive model had 64Mb.

I pulled the...

Upgrading on-board components on hard drive controller boards?