How to know what driver

How do you know if a driver matches up to how many cobs are how hard you trying to run them. Here is an example. I've got 8 3590 72v coming from Kingbright. I hope this week! I ask the forum what driver I needed to run for 4 3590 and people told me the mw 185 700 but how do you figure that out? Why not 185 1400 ? What would happen if you hooked them up to the 185 1400? I'm not going to but just wonder how this stuff works.

At 1400mA, the CXB3590 72V class would dissipate ~104W and forward voltage would be ~74.25.

The HLG-185H-C1400 maxes out at about 143V, so you could use one COB on that driver but since this driver cost $60 there are cheaper options to do that job. If you put a pair of CXB3590s in series you would need 74.25V X 2 = 148.5V. Since the driver cannot go up to that voltage it will reduce the current output until the voltage reaches ~143-144V. In this case it would have to reduce current to ~1050mA, so each COB would dissipate ~75.5W.