I can not go more than 375 2 cubes at corsair 1200i more 375
Shut down psu

What the ff
......

I saw the same thing with my Corsairs, they don't like you to push too many watts over the PCIe connector, I moved to EVGA PSUs..

The answer to your first question is yes.

The second question is yes..to a degree.  Yes in that the cables from your PSU will see less load and therefore less heat/chance of melting.  This adapter as is with regular pins and 18AWG wiring still has the same risks as if you used a regular PCIe cable.  The difference is that it is cheap and easily replaceable.

The upgraded version I have in mind will probably be overkill for this application but that is how I roll.  Molex makes a line of minifit pins suitable for high current systems that allow up to 12A instead of the regular 9A.

I have a corsair 1200i on my computer that would constantly shutdown when the gpu's pulled more than 20A. I have dual water cooled 7990s. I have enabled multi rail OCP in the Corsair and use over clock protection to adjust the rails to allow more than 20A. I am using the Corsair link software to do this. I don't know if there is a way to do this without the software because the default is 20A. So this is probably why more than 2 cubes will shut down the psu. Just my thoughts.

I dunno:

DPS2000-BB.  These PSU's are rock solid.  I run 5 Neptune boxes off each one.  No issues whatsoever.

Notice the slider is all the way to the right to get 40A. You can only activate it by checking OCP otherwise it will default to 20A.

Corsair say's the 1200i is single rail but it really isn't. It has multiple rails that have OCP protection to 20A. You can increase the OCP protection beyond 20A using the link software. This power supply is designed to work best in a PC where you can over clock the rails to 40A using the link software.