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 XD5 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 D5 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 max 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 with excellent overall performance, the integrated pump top in the CORSAIR Hydro XD5 does not disappoint.

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 D5 is rated at 1500 LPH (liters per hour, 6.6 GPM) of max flow, which is great to look at but corresponds to an open loop with no liquid-flow restriction. Close the loop and it is reduces to ~4.1-4.2 GPM. Add in your everyday closed-loop components and you are looking at a max flow rate of ~1-1.2 GPM for most setups. 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.


Things get a lot closer here, and the CORSAIR Hydro XD5 does a very good job at keeping things flowing quietly. It is bested by the new Alphacool VPP755 at the higher end and in noise output, but the Alphacool VPP755 does not yet have the proven long-term reliability the Xylem D5 in the CORSAIR Hydro XD5 enjoys. There are a few more budget pumps that do a decent job in terms of performance/noise, but those wanting the best-possible performance at reasonable noise levels will look at the Xylem D5, which makes the CORSAIR offering a strong option.

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 (reflected above in the Swiftech MCP35x) have both been in use for years in some of my systems and those of others. The D5 especially has lasted through the test of time, which is another plus for the CORSAIR Hydro XD5. 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.