Two Pumps in Series, 2 DDC 3 or 2 D5?

[Registered User]

Despite not very significant on the improvement. I suppose but increasing the flow rate at each waterblock, I should be able to see a decrease of temperature on those components being cooled by waterblock.

I've been thinking of runing two pumps in series to achive higher flow thru restrictions created by having 3 waterblocks, 2 3x120 radiators, and additional radiator(s) or waterblock(s) might be added in future.

The objective is simple, high flow with high head count.

Two configuations currently in my mind are:
1. 2 DDC 3 in series
2. 2 D5 in series

DDC 3 has higher head count but lower flow rate whereas D5 has higher flow rate but lower head count. Any suggestion on how to get the best out of these two pumps would greatly appreciated.

FYI, the loop is curently being pumped by a DDC 3.25 with XSPC top. I have both DDC 3.25 and D5 (with speed controller, stock), and from the flow indicator of the EK-BAY SPIN reservoir, I noticed tht the speed of the flow indicator spins slower when D5 is fitted (with speed controller set at #5) and with DDC 3.25 fitted, faster spining speed of the flow indicator has been noticed. But since I don't have any flow rate measuring device, I guess I juz can't simply judge by looking at the speed of the flow indicator, can I?

OK, now back to the question, which one would U guys suggest, 2 DDC, 2 D5, or no second pump is needed?

[Utnorris]

I found two DDC's give me slightly better flow over two D5's in my loop. Not much, but some.

[Registered User]

Should I expect any temp. difference between these two configurations?

[CedricFP]

The dual D5's will dump a bit more heat into your loop. If you have enough radiator, that will not be measurable in terms of CPU or GPU temp readings in OS. If you don't have enough radiator it could be, possible measurable.

You also see pretty huge diminishing returns after 1GPM, generally. Head pressure here is the more valuable in the flow vs head tradeoff at flowrates of above 1GPM, generally.