Thanks man!
Roughly 7-10C drop in temps, depending upon the ambients. A single D5 can easily handle this configuration. Out of its 1~5 speeds, where 1 is the slowest and 5 is the highest, I'm running it at 1.5
It doesn't matter how fast the fluid is flowing, that doesn't have any effect on temps, some people misunderstand this fact.
2500K @ stock and three 670's with no botteneck from the CPU? I remember I could run my 2500K @ 5.2Ghz without it breaking 60C with a Silver Arrow, those chips ran cool at 32nm due to hardly any transistor density causing heat issues, keeping the fluxless welded IHS on a side.
I could have gotten the 1080 Nova for half the price, but this I found to be a lot better build and also made in Germany (WaterCool), so it was obvious.