I have this review now published on my new website here, or you can get the details below:
Welcome to my living review of the Koolance RP-402X2 and RP-452X2 drive bay reservoir systems. First, I would like to give a huge thanks to Tim from Koolance for sponsoring. The RP-402X2 and the RP-452X2 are the latest in the dual bay pumping reservoir craze.
Koolance RP-402X2 & RP-452X2
These are exceptionally well made "Acetal" reservoirs that can hold and run two (PMP-400, PMP-450s, or PMP-450S) pumps all in a single dual bay reservoir. These also have two independent reservoirs that can be run independently, shared, or in series depending on your desired setup needs.
RP-402X2 is designed for the PMP-400 pumps
RP-452X2 is designed for the PMP-450 pumps
Both reservoirs share the same reservoir system with only slight modifications made to accept each type of pump. I'll spend some time going though various tests and review items below
For performance testing I am employing my usual pump testing tools. Flow rate is measured using a King Instruments 7520 flow meter. Pressure differential is measured using a Dwyer 477-5 series digital manometer. Voltage is measure at the pump plug to eliminate vdroop. Power and Amperage is measured using my Mastech power supply.
It's a heavyweight! All 5 pounds of it when loaded..wow! This is a tribute to the massive machined acetal block construction.
This picture shows removal of the machined block off plate for two pumps on the 402 model. The reservoir comes with this installed so you can run one pump and upgrade later to two pumps if needed. It also comes with G1/4 plugs on the back. If you remove the reservoir side plug, you can use both reservoirs for one pump. Many operational options exist within. I'll include some configuration options later in the review.
The 452 series uses large aluminum threaded couplers to screw the pumps into place (These are not in contact with water). This photo also provides a quick look at 3/4" (19mm) OD compression fitting spacing:
More internal pictures - Very easy to take apart and clean or modified as needed:
Performance PQ Chart
This is testing the pressure head capabilities of the entire pump operating range, but generally you should be most interested in the .5 to 2 GPM range as that is typically where most water cooling systems operate. The benefit of this type of testing is that you can estimate flow rates with the data collected and you also evaluate the entire operating range.
Single Pump 402 Series PMP400 (DDC3.25)
Single Pump 452 Series PMP450 (D5Vario)
Two Pumps 402 Series (Plumbed in Series)
402 Series Comparison
This is a bit of an apples to oranges comparison, but in single pump mode it produced slightly less performance than the COV-RP400 (WITHOUT RESERVOIR), with a reservoir included in the standard pump test, I suspect they are roughly about the same. I will do more combined testing on this in a bit. That's all fine and splitting hairs, however if you really want power, running two pumps in series or two separate loops will make a much more noteworthy difference. I found the reservoir to scale nearly double as you would expect, this would be much more power than needed for even the most restrictive of loops.
452 Series comparison
The RP-452X2 has a small performance advantage over the stock pump top plus reservoir curve in the .5 to 2GPM range, which is great. The stock PMP450 top is generally good so any little gain or even matching should be considered a good top.
Performance PQ RP-452X2 + PMP-450 + PMP-450 Series
Overall, without a doubt the noiseless enthusiast dream. I really like this setup, it scales so well with noise and power needs. You can easily dial it down to ultra slow speeds and up to intense pumping power that can easily surpass the 1GPM barrier on any system. It's also amazing how quiet the setup is, I've got some videos for you, but at Setting 3 to 4 it has more than enough power for average systems and practically inaudible (Less than 1dbA raise in noise level)....just awesome for ultra low noise..
Setting 1 -(+.4dbA over 41dbA ambient) For Ultra Low Restriction. A bit low in power for my taste, but it could net you around .75GPM with a very low restriction setup.
Setting 2 -(+.5dbA over 41dbA ambient) For Average/Low to Low Restriction. Another ultra silent setting with a good amount of power for Average/Low to Low Restriction. A low restriction single block loop would see around 1.2GPM which exceeds the desirable 1GPM rule of thumb. But if your emphasis is low noise, you could also do well with this setting on an average restriction loop. (Low restriction CPU block plus 1-2 GPU blocks).
Setting 3 -(+.6dbA over 41dbA ambient) For Average to Low Restriction. This would be my personal favorite, it has an exceptional noise/pumping power ratio and will have plenty of power for a little above Average to Low restriction loops. A low restriction loop would see around 1.5GPM, and an average restriction loop around 1.1GPM.
Setting 4 -(+.8dbA over 41dbA ambient) For High to Average Restriction. A low restriction loop would see around 1.8GPM, Average about 1.3GPM, and High around 1-1.1GPM. This is a fairly strong amount of pumping power good for your higher restriction 3-4block type systems. Noise level is still very good, but just slightly more audible over setting 3.
Setting 5 -(+1.5dbA over 41dbA ambient) For Very High to Average Restriction. An average restriction loop would see around 1.6GPM with this setup and even the most restrictive 5+ block loops will see 1.1-1.2GPM which is very healthy. I simply can not see where this isn't enough pumping power.
And here is the family of curves for easy setting comparisons:
So which pump you might ask?
I feel this becomes largely a personal preference or personal inventory decision. If you already have one or two of these pumps in any flavor, then the choice is fairly clear in saving on pump cost. I personally am a bit of a noiseless priority type so I find a bit more appeal in the 452 plus a pair of PMP450 pumps. This setup allows you to control pump noise and power via the built in PMP-450 controller, and two pumps in series is an intense amount of power regardless of the flavor. However if you have pump voltage control capabilities, the PMP-400s also provide that flexibility perhaps even via computer control or on demand control.
On the test bench I found the noise level with both pumps in series to be roughly the same as running a GTAP-15 at full speed. That large mass (5 pounds) is a large benefit to keeping vibrations at bay.
Here is my preliminary 402 series test run:
And a similar test with the 452 series:
Subjectively I think the 452 series with PMP-450 pumps is a bit quieter than the 402 series with PMP-400 pumps. If silence is a really high priority, I would suggest the 452 model and PMP-450 pumps. That would give you an easy means to reducing pump speed on the built in pump controllers. Alternatively you could use voltage control on the PMP-450S or PMP-400 pumps. The nice part of running dual pumps is that you nearly double pressure head over one pump, so in general you can dial the pumps down to about half their speed for the same amount of power as just one pump.
Exemplary, this is one of those products that gives you joy just holding it in your hand. The machining and heft of the solid mass of acetal inspires confidence in durability. The entire rear portion of the unit is one massive block of machined acetal. The only joint is the face plate, but it too is reinforced by an aluminum bezel to spread the load of the mounting screws. They even go to detail of machining chamfers on all areas, it's really a work of art. This is by far the most well constructed and durable reservoir system I have personally had the pleasure of testing.
Configuration Options for two pumps
Hard to explain and I'm a visual guy, so this should work..
The above requires some sort of connecting loop or elbow combination, but that's not the only way to do series. You can also simply bridge the series with some components in between like the schematic below. That would eliminate the need for any elbows, etc.
Priming & Filling does take a little patience particularly for the P1 pump due to the inlet port being relatively high up in the reservoir. I found it to work best by initially tipping the case on it's back and using the front ports to get water primed quickly down into the pump. Then seal off those plugs and switch to the top ports. To get the last little bits of air out you have to tip the case to the left or right opposite of the port since the port hole is in the upper corners. It may also be advantageous to plumb the upper fill ports to remote fill ports on the top of your case. This would allow some fluid to be stored outside of the reservoir and make topping off a less frequent occurrence. Just take your time with this and plan on cycling the pumps on and off to avoid running the pumps dry. Also plan on tipping the case around and on back to help.
Once the system is filled and flowing bleeding actually works very well. The baffles in the reservoir do a great job in providing calm water for air to bleed, although the right reservoir does require topping off fairly full for best results.
Both units come with the same channels and predilled holes to accept up to four 3mm LED lights. Two are located on the upper side corners and two on the bottom side. The actual LEDs do not come as part of the package, you have to order those separately.
In this example I used some 5mm LEDs and just pushed them up flush against the acrylic. I also applied a strip of electrical tape around the perimeter to prevent any lighting around the edges.
This is using water only and using 4 red 5mm LED lights, I also had the two edges covered with tape, as you can see a little light is escaping the top edge:
The following picture is using only the two top LED slots and I had electrical tape around the entire perimeter:
What's not to like about taking four very difficult to place components and packaging them in one dual bay unit...amazing...
I am very happy with both reservoir systems, particularly for their exemplary build quality. Performance on both units is roughly equal, the 402 series is a fair amount better than the stock top and the 452 series is slightly better. Both very good setups each with very minor differences. The differences really come down to which type of pump you like or may already have on hand.
If you REALLY want to kick it up a notch, go with two pumps!! Two pumps in series worked very well and scaled the single pump test 2:1 almost perfectly for head pressure. All 14psi at max (shutoff head), and about 9PSI at 1.5GPM is some heavy duty pumping power on the 402 series. I have a hard time imagining where this wouldn't be enough pumping power. Keep in mind that flow rate has relatively little impact to CPU temperatures above about 1GPM, so don't expect that going to dual pumps is really necessary for all systems. I would do it for pump redundancy safety reasons, for having the ability to reduce speed/noise of dual series pumps, and for getting every last drop from you blocks.
Regarding the pump redundancy thought. I ran a quick test and found that with both pumps operating at 1.5GPM, if I turned off one pump, the result was 1.1GPM which is still plenty to keep the system cooling properly. Some people have thought that a pump stopped adds quite a bit of restriction, but the test didn't show that. I only lost about .4GPM which means a stopped pump is very free flowing.
My only challenge was getting the system filled and bled of air. I'm not very experienced with bay reservoirs, but this one did require that I tip the case on it's back and on to it's side in various angles along with intermittently cycling the pump on/off to slowly get the system full of water without running the pumps dry. This took me about a hour or so and more patience than expected. In the end I was able to get the system full, but don't expect that it'll be easy. Also note that the reservoir side doesn't necessarily match up with the pump and outlet port side. I also would recommend using the left side reservoir in single pump operation because it's in/out ports are located at the bottom of the reservoir which makes bleeding easier. I'm not sure there is any way to improve this, it's simply a fairly compact set of reservoirs connected to the pump via channel ports that takes some effort in filling. I've managed to get mine filled both with a single pump on P1 and with both pumps in series. I was successful both times, but it did test my patience.
Noise was good, I didn't observe any obvious vibration induced noises in my extereme silence case test with the 402 series although I would suggest the 452 series and PMP450 pumps for best noise results. I generally had a fairly difficult time trying to measure noise particularly in my more informal bench tests where I had a bit of ambient noise present, and particularly when another fan was adjacent to the pump. Ambient noise masking makes a significant difference and is beneficial to any perceived pump noise. Pump noise for your average fan user will not likely become a concern, but for those into the sub 1000 RPM fan setup, I would definately recommend the 452 series with PMP-450 pumps. This setup provides a very noise tunable solution for even the most particular noiseless users. My personal noise favorite is the 452 series with PMP-450 pumps turned down to setting 3. This gives you a huge pumping power range, complete noise control, pump redundancy, and cool pump operation.