wrote:
ThinkPad P50 has the option to install two 2.5" HDD. However, "Hard disk drive cable" is needed.
Per Lenovo, there are two different part numbers:
00UR835 Cable,HDD,slot3
00UR836 Cable,HDD,slot4
Obiously, one is the the bay on the left and the other one if for the right.
I just ordered a 20EN0013US. It comes with a 500GB HDD, which is on the right bay.
If I shall add a 2nd HDD, I'm going to use the bay on the left. Now, my question is - is the bay on the left slot 3 or slot 4? Which cable I'll need?
Not clear to me which one is which one.
Lenovo's English terminology in referring to "slot3" and "slot4" unfortunately does not correspond to those terms in any diagram. They should have used "bay" or "slot" when applicable.
There are obviously two drive bays, left and right. These should have been called "left bay" and "right bay", or maybe "bay0" and "bay1" rather than "slot0 and "slot1" as the diagram on page 64 shows.
And then inside the left bay for M.2 there are actually two PCIe connectors/slots, also designated as "slot0" and "slot1" in the diagram on page 66.
Ambiguous and confusing terminology, to call a "bay" a "slot", and use the identical "slot0" and "slot1" for two different laptop locations.
So, it's now clear what HDD0 is, i.e. the factory drive in the right bay). And HDD1 would be the optional second non-M.2 drive installed in the left bay, if you choose to use it that way.
And HDD2/NVMe0 would be the leftmost PCIe slot inside the left bay, and HDD3/NVMe1 would be the rightmost PCIe slot inside the left bay.
As to what "slot3" and "slot4" pertain to in terms of which of the two different HDD cables are available as shown in the PSREFs document, well it's anybody's guess. Lenovo obviously meant them to distinguish between the cable needed for use in the left bay vs. the cable needed for use in the right bay. But the terms "slot3" and "slot4" are not used in the HMM, so who knows which is which.
I would hope Lenovo updates the HMM to clarify, revising it to use proper non-ambiguous and non-duplicated English terminology. It would also be nice if they added another diagram showing this optional alternate configuration supported which places a second 2.5" HDD in that left bay, including how the drive gets physically installed and where the proper left cable for the left bay connects to. Mention of the proper part number for the required left cable would also be very useful (and would, of course, be the answer to your fundamental thread question).
But again, I suspect one of these (right cable) is a straight SATA->SATA cable, for use in the right drive bay where a SATA connector to the motherboard must exist. And I'm guessing the other cable (left cable) is a SATA->PCIe cable, for use in the left bay where there are only two M.2 PCIe connectors. As to which one is for use in the theoretical "slot3" and which one is for use in the theoretical "slot4", well maybe Lenovo Parts can clarify with a phone call.