Correct. Performance shouldn't be an issue if you confirm the following:
- verify the 16x slot actually has 16 lanes going to it. Some motherboards only run the full lane count to the top slot.
- verify your motherboard supports 4x/4x/4x/4x pcie bifurcation for 3-4 drives, or at least 8x/8x or 4x/4x for 2 drives. Without this feature, only 1 drive will show up regardless of how many you put in there.
- make sure you have enough pcie lanes to support the number of cards you want. In consumer hardware pcie lanes are often shared among several devices that are plugged in.
As an alternative to the 2nd one, you can buy very expensive pcie adapter cards that have a chip onboard, saving you from needing bifurcation support.