i’m a little confused about the internal m2 ssd slots and the expansion slots
if i want to add ssd cache to improve the performance of the ts-873 is it better to use the internal m2 ssd slots or to buy the expansion card and put the cache there?
The ts-873 comes with M.2 slots for dual SSD cache sticks. But you can also add cache drives in any of the HDD bays on the NAS itself. And of course, you can also put SSD inside the bays of expansion unit.
The speed will be exactly the same wherever you put M.2 or SSD, because they all will operate at SATA speed- 6Gb/s.
The story is very different when you install NVME cache card. This SSD will for around 5 times faster than regular SSD. Qnap sells QM2-2P card with and without 10GbE port which is a next logical step with such a speedy improvement.