Originally Posted by Kung Pow
I did some calculations.
I wanna keep the pump slient so I intend to run it at speed setting 3 / 3300 rpm = 3 GPM with the EK X D5 Rev. 2 Top ....or max 4 /4050 GPM = 3.25 GPM with the EK X D5 Rev. 2 Top
1 GPM = 227 l/h (Just for comprehension matters)
My EK Supreme HF Full Nickel allows a flowrate of 1.59 GPM - 360 l/h.
My Phobya G Changer 360 allows a flowrate of 1.98 GPM - 449 l/h.
My EK Waterblocks GPU Block allows a flowrate of 1.75 GPM - 398 l/h.
My Phoba Xtreme 1080 Rad allows a flowrate of 1.69 GPM - 384 l/h.
The average flow of 1 x D5 with EK X Top Rev. 2 should be 1.75 GPM in my system.
Two would approximately result in 3.5 GPM -/+ 0.5GPM .
If I calculated right these are the end results
Edit: Charlie I do not understand why you said the Kryos would be too restrictive for my system and my temps would get high? Even with the 1.25GPM the Kryos grants my average would still be over 1 GPM easily. So what benefit do I know have from switching it with the EK Supreme HF Nickel?
That's not how you calculate flow rate. You have to make an estimate of the pressure/flow curve for your components, and then place it onto the pump's power. Since this is very hard, it is best to just check whether you will get over or under a particular flow rate. I will use the flow rate of 1 GPM as it is generally seen as the flow rate where temperature gains begin to become minimal.
Step 1) Find out how powerful the pump is at that flow rate
I looked to Skinnee Lab's testing of the Laing D5 and found this graph for setting 3:
The Laing D5 with the EK X-Top has 2.25 PSI of head pressure at 1.0 GPM. Since you are using two pumps, double the number to 4.5 PSI.
Now, let's add up the total restriction of these components:
Your radiator pressure drop data was also done by Skinnee Labs
So, we are at 0.38 PSI at 1.0 GPM of flow.
Now for the GPU block. While I don't have any exact data on the EK Waterblocks GTX 295 block, all other reviews of EK GPU blocks have had 0.8-1.0 PSI of drop at 1.0 GPM of flow. Let's take the higher end estimate to be safe. Add that to the total and we are up to 1.38 PSI total drop.
I also have no data for the CPU block, but based on some rough calculations based on a few reviews it should be around 1.6 PSI at 1.0 GPM
Total is now 2.98 PSI.
Add in the 1080 Radiator. I will simply assume it is 3x the restriction of the magicool 360 (as that's what the radiator seems to be, 3 360 radiators in serial) 1.14 PSI drop. Total is now 4.12 PSI. That leaves 0.38 PSI of headroom for fittings and tubing. I'd say with that setup you'd be getting just over 1 GPM.
Now, with the Kyros XT, which has roughly 2.5 PSI of drop at 1 GPM, that figure would be increased to 5.02 PSI. Thus you would be forced to turn the pumps up to setting 4.
Now that we have gotten all of that out of the way, I would suggest that you do NOT get dual MCP655s. With the cost of the dual top and the two pumps it would be a better idea to get a single MCP35X and use the PWM control on the motherboard to keep it nice and quiet.