Pump Top Performance Testing

With the pump isolated and tested, it is now time to see how the integrated pump top in the CORSAIR Hydro XD3 performs. I will say right away that this was done before the pump was tested and even prior to disassembly since this test is done with the product out of the box, but the story flows better with these results after those of the separately tested pump, so here we are instead! For this test, I used the same pump on various Xylem DDC tops from various companies—some standalone, some integrated into reservoirs. The testing methodology to generate a P-Q curve was the same as before, though only with 100% PWM duty cycle this time around.


There is a fair amount of variation from top to top, with some focusing on providing a higher maximum head at the expense of flow rate and others going the other way. A good balance of the two ends up being the best overall in realistic scenarios, and the integrated pump top in the CORSAIR Hydro XD3 has a middling performance here.

A Realistic Loop Test

So far, we have seen the results for extremely controlled tests, often to minimize the effects of involved variables. However, this does result in an incomplete picture by focusing on the possible maximum as opposed to realistically achievable values. Take a pump's P-Q curve, for instance. The Xylem DDC pump is typically rated with an open loop with no liquid-flow restriction, although CORSAIR does do one better with closed-loop numbers. Add in your everyday closed-loop components and you are looking at a maximum flow rate of ~1–1.2 GPM for most setups with such pumps compared to the much higher number many companies tend to report. This is where the budget pumps come in and why you should consider all options.

I used an XSPC Raystorm Pro CPU block, Swiftech Komodo R9-LE GPU block, Black Ice Nemesis GTS 360 radiator, and two sets of Koolance QD3 quick disconnects with six Bitspower 1/2" x 3/4" fittings and Primochill Advanced LRT tubing in the same size. The blocks are one of the least restrictive in each category, and the addition of the QDCs and relatively more restrictive radiator brings the average restriction close to what most loops would have. At the same time, I measured pump noise alone by placing the setup inside an anechoic chamber at 19 dBA, with a sound probe 6" away from the pump. No other sound sources were inside the chamber when these measurements were taken.


We see here how the CORSAIR Hydro XD3 performs very well, but is louder relative to others for the performance you get. The Xylem D5 as part of the CORSAIR XD5 is a generally better option if you can fit it into your build, and I have also added the DDC-like Swiftech MCP50X that is even more biased towards a higher rated head pressure and lower rated flow rate, which is extremely loud at full speed, but does better once slowed down. Given the nature of so many moving parts inside a pump, reliability is hard to talk about within a review's time frame. It is thus helpful that the Xylem D5 and DDC have both been in use for years in some of my systems and those of others. Since there are so many hard-to-quantify variables when it comes to a pump, I will refrain from making an attempt at a relative performance chart and, as such, a price-to-performance chart.