Oh I did not know about 5V dummy load. What kind of load do you suggest to put on 5V?
Google found this:
https://pcbsmoke.wordpress.com/2012/11/21/converting-an-atx-power-supply-into-a-dc-bench-supply/"Q. Which power rail do I install the dummy load resistor on?
A. As a general rule, you install the dummy load on either the +5 volt rail or the +12 volt rail, whichever one has the most power."
Modern Power supply have most Power on 12 V and since we already connect GPU and risers maybe we don't need any dummy load?
connecting 5V (red) with the ground it's enough. 5V dummy load on 24 Pins just to make sure our PSU produce the right wattage, you can measure it your self. if without dummy load your PSU produce the right wattage, you don't need to do it.