Cable did the job

My Problem

User was experiencing a spinning pinwheel for nearly everything and system would eventually slow to a crawl. After upgrading to a Samsung 1TB SSD and a fresh install the issue improved but still did not run as expected. I was afraid this was a main logic board issue but after reading some comments decided it could simply be the hard drive cable.

My Fix

Very simple install, nothing really to add.

My Advice

This seemed like an unlikely part to fail but if you have similar symptoms give it a try. Thinking about the other MacBooks I've worked on this might be a more common problem than I expected.