I have just finished installing an upgrade with another D5 and 3 x 360rads to a dedicated cooling case. I was looking for advice on if I have the optimum setup for flow with 2 x D5's in series. Res > D5 > External out > CPU > 3 x GPU series > Mobo > Ram > External return > D5 > 3 x 360Rad series > Res I have improved flow over the single D5 but I have also replaced a 240rad and added an additional 360 for a total of 3 x 360 rads. I expected to introduce more restriction with an extra Rad but i don't think I have the flow I was expecting with a 2nd D5 in the loop. 2 loops could be done but i was hoping for better overall cooling. I know I will pick up a bit of flow when I fit the koolance SLI links for a parallel setup on the GPUs. The water now idles at 28c which is 4c above ambient and peaks at 45c under full system load with the OCCT powersupply test after 30mins. Overclocks are i7 930 4.2Ghz @ 1.34v vdroop2 QPI/VTT 1.4v - Apogee XT WB - idles 40c peaks 70c under OCCT after 30mins Gigabyte UD9 200Mhz BLK IOH 1.4v ICH 1.3v - NB idles 42c peak 48c - EK blocks 1 x 5970 950/1300 1.3v idle 34c peak 55c - EK block 2 x 5870 950/1300 1.3v idle 33c peak 55c - EK blocks 1 x 8800ultra (on stock air) 3 x 2GB Ram DDR3 1600 1.6v on water but no temp data - Koolance Blocks Rads all have pushpull coolermaster 90CFM fans at 1800RPM under max load. I can run 4.4Ghz at 1.46v but CPU temps jump by 8c to 48c idle and to 88c under load. Does anyone have any experience with dual D5s and long loops? Should I run the D5s in series before all the blocks and rads or is how ive got it setup now in series with 1 D5 before blocks and another D5 before Rads the optimum? cheers and thanks.