Finally has screwed up the optical drive sata port

I used to throw in a ssd in the optical drive port for raid 0. But after the update to windows 10, I could not get the raid setup working under uefi. (which actually saved my butt later) So I went with just two separated drive setup. One ssd for system and another for storage(in the optical drive bay with a caddy).

One night I was doing a batch file transfer of my steam file from the external harddisk to the storage ssd. It was a batch of over 300000 files of a total 70GB. Since I use tera copy to verify file integrity after every copy, this could take a few hours. I left it through the night. The next morning, it was still copying and checking sum, but extremely slow. It should have finished hours ago. I cancelled the transfer and ran crystal disk mark, found that the storage SSD only has about 20MB/s read speed!! (write is normal though)

Since I just replaced the hdd caddy ( actually from a cheap brandless one to a silverstone), I suspected it was the culprit. After some tests, now the ssd can be recognized in bios, it can no longer be reliably recognized by windows. Sometimes it boots with sata 2 speed, sometimes the system fails to boot.

Tests I've done:
1. Swapping back to the old caddy -->same issue
2. Testing the ssd with an usb adaptor -->ssd is fine
3. Testing the caddy with mini sata to usb cable -->ssd and caddy are fine
4. Erasing and reformatting the ssd for several times -->same issue

I concluded it was the sata port (or the controller) failing. I've already broken the fragile clip holding the ribbon cable of the optical drive cage. It is totally possible I screwed up the port with so many drive swaps through the years.

I gave up testing it and stick with the one drive. I could send it in for warranty but after hearing the many horror stories of defected machine cycling, I choose not to risk it. Especially because it's a discontinued model.

I am not writing this post to ask for a solution. But will appreciate if someone can shed some light on it. I can accept a 3 years old machine to have some problem and can live with one drive. (which is still a very smooth experience). Using that stupid fragile ribbon cable is a design flaw imho. A laptop this thick and bulky Dell could certainly put a more robust connector on it.