My xspc 750 pump broke, primarily I believe because it was working so hard to try and push through the amount of restriction I was running (cpu + 3 gpu in series + motherboard block + 2 rx360). I had seen before that I had to lower my 990x overclock from 4.8GHz to 4.65GHz when I went from cpu only to my full loop. Because of this I knew I needed some serious pumping power, so it was time to go with the king of the hill - the PMP-450s. According to Martin's liquid lab, this is the highest flow rate pump when run at 24V, beating even the mighty ddc 3.25.
Photos to come soon!