The EK D5 X-Top Rev.2 is the second revision of the EK D5 X-Top, this revision is entirely different from the original except for the EK styling and quality. Unfortunately, results were never released for Rev.1 and the performance numbers have always been left to speculation. Thanks to the Liquid Cooling community and their everlasting search for performance numbers coupled with the generousity of Eddy, we will not have to speculate on this revision.

The EK X-Top Rev.2 fits the Laing D5, which is re-branded by Swiftech (MCP655) and Koolance (PMP450). This top is a full replacement for the stock top that we all have become used to on the D5. Aftermarket tops have become standard for the Laing DDC series, but the D5 is new territory, I am happy to see another option for the D5 as the stock top has always left the users wanting to customize and push the solid D5 further.

Pump Curves or P/Q (P is pressure, Q is flow) curves are derived from two measurements, flow and pressure, and the P/Q curve is just a visual representation of the relationship between flow and pressure. For the curve, maximum flow rate (GPM or LPM) is the X axis and Pressure (PSI, mH2O, ftH20, mBar) is the Y axis.

Almost every pump specification I have ever seen comes with a defined maximum head (or lift) and maximum flow rate. Problem with these curves is they are based on perfect world conditions, where no restriction or resistance are factored into the data and resulting P/Q curve. The key for testing is setting up a test fixture to collect data for all capable ranges of the pump and top in order to develop a real world P/Q which uses the common components in a PC Liquid Cooling System, and that is exactly my goal for each Pump and Top test performed in the lab, we aim for real world scenarios and the resulting data.

One other item to note on P/Q curves is the Trendlines used on the scatter plots. DDC's trendline has a best fit polynomial using a 3rd Order, where as D5's have a best fit with 4th or 5th Order. Now the problem I am running into with Excel is a defect that has been around since Excel 2000 and polynomial trendlines and forecasting/prediction. Sometimes no matter what you do, the trendline will not work on a best fit with prediction, the code inside Excel is not consistent. As a result, some of the trendlines you see on the individual test reports will not represent the proper trendline. Additionally, I did not forecast or predict ahead on the compiled P/Q curves for all results, some did not have the Excel bug and some did.

In short, dynamic head pressure is the pressure measurement at the outlet minus the pressure at the inlet or the differential. Dynamic head pressure is a better measurement for the actual pressure the blocks will see in the loop. Many other pump tests have only measured the outlet pressure, which does not take into account the inlet pressure and does not represent a true pressure measurement for your cooling loop. Dynamic head pressure is quite easy to add to the Pump test fixture and requires a T fitting at the pump inlet and a T fitting at the pump outlet. The pump inlet T is hooked up to the negative side of the manometer and the Outlet T to the positive side of the manometer.

I took Martin's lead on this measurement and included these in the individual test results that you will find at the bottom of each speed setting graph. For each flow setting the voltage was regulated to 12.00 volts as set on the DC Power Supply and verified on the multimeter hooked up for all tests. In addition, the current (amps) draw was recorded for each flow setting, luckily the DC power supply I have has a display for amp draw, initially I had a multimeter hooked up but as tests went on the two displayed identical readings. As with Martin's tests, the voltage regulation and amp draw data recording is really used for the efficiency charts, but power consumption is displayed on the P/Q curve charts for your reference as well.

No shocker here, another test result that was started by Martin and I only feel that it is right to continue providing the information. The efficiency charts are simply a graphical depiction of the water horsepower to break horsepower of the pump at the given flow rate, showing which flow rate the pump (and pump top) will perform with the best efficiency.

Here are the compiled scatter plots of the two configuration options for the EK D5 X-Top Rev.2 as well as the Stock D5. Below each scatter plot is the test data for each inlet/outlet configuration at the specified speed setting. The Performance Results Intro section of this page explains how to read the charts and the explanation of the data. Enjoy!

The EK D5 X-Top Rev.2 was a different design that I was not anticipating, aesthetically I figured the design would be similar to the Rev.1. The change in design is definitely a plus, the backplate and dedicated mount plate are welcome changes. The capability of a top outlet or front outlet are also big benefits to the EK. This configuration option when laying out your loop might just be the piece you need to route tubing in a better manner. In addition to tube routing, the performance gains are only slightly reduced when using the front outlet over the top outlet. As with another of the D5 tops, the only real gripe I have is the mounting method. If you have previously drilled holes in your case for the stock D5 mounting bracket or (UN)Designs bracket you will have to drill at least one new hole to accomadate the EK D5 X-Top Rev.2 mounting plate. The stock mounting bracket or (UN)Designs bracket cannot be used with this top.

Overall, the EK D5 X-Top Rev.2 is a great aftermarket D5 top. The top brings very nice performance gains from both outlet configurations. A well designed top, with backplate and mounting mechanism. If you're in the market for a D5 top, you cannot go wrong with the EK D5 X-Top Rev.2!