This review hopes to answer those questions.
The pumps come in very plain white boxes without even the Koolance logo that graces their other parts.
The pump itself is very large with the accompanying top. In the background you can see that it's almost as large as a 5 1/4" bay.
The top easily unscrews for mounting after market tops or fitting in a compatible reservoir. As you can see the wires are beefy. This is good because this pump can use 55W when run with the maximum voltage, and probably more when stalled or dry heaving.
To get the most of these pumps you need a 24V supply, fortunately Koolance sells one designed for this load. As I was planning on testing 2 of these pumps, it made sense to buy the dual 24v controller. It's identical to the individual 24v controllers, but both controllers get mounted in a pleasant to look at 5 1/4" bay. The controller looks like it's designed to match the RP452x2 reservoir as the cutout matches with the right reservoir when the controller is mounted underneath the reservoir. Unfortunately the brushed aluminum of the controller faceplate is not perfectly the same as the RP452x2.
1. Low restriction loops:
Test HW- i7-990x @ 4.43GHz 1.41Vcore, 1.35VQPI, loaded with stresscpu2 on redhat 64
I tested 2 blocks as well as with 1 or 2 radiators, and 1 or 2 pumps at 12 and 24V:
Martin claims that the PMP-450S at 12V is similar to a D5 Vario at Setting 4. From this data we can see that 1 "normal" pump is insufficient for all but the lowest of restriction loops (even the rasa block with 1 radiator) is too restrictive.
We can also see that 1 strong pump at 24V performs better than 2 normal pumps in series for "medium" restriction loops. It also costs significantly less. For very low restriction loops it may dump more heat than it's worth, but here the variable voltage control will help you fine tune exactly how much flow vs heat dump you want.
2. High Restriction Loop
Test HW - i7-920 @ 4.2GHz with XSPC raystorm cpu block, Rampage III Extreme with EK full cover block, 3xGTX480 with Koolance full cover blocks in parallel. Loaded with folding at home (SMP-6 on CPU + 3 advmethod WUs on GPUs)
Here you can see the extra pumping power of two pumps in series with various combinations of voltage:
Some things to note- low pumping power and high pumping power hurt temps, because of low flow and high pump heat dump respectively. In the middle most pump settings are equal with a comple of points that favor gpu and cpu respectively.
This may change significantly with gpu's in series rather than parallel. This will be my next test when I tear down my loop and I'll update this post with the results.
What does this mean?
A single PMP-450s with a 24V contoller is sufficient for almost all situations. For high restriction high power loops, you may get slightly better performance with 2 pumps, however, the second pump could be a regular D5 style pump. As a PMP450s with a 24v controller is significantly less than 2 pumps with a top, it's a very good choice for those who aren't concerned about every last degree.
The PMP-450s is an amazing pump, at 24V it does similarly and in some cases better than two regular D5's in series. As it's similarly priced to a regular D5, you can simply buy it, and add the 24V controller for $40 later on. I would highly recommend it, however I wouldn't recommend two of them at 24V in series, unless you have an extremely high restriction loop and really care about temps.