A pair of water coolers compared

Two of the more interesting water cooling kits on the market are Corsair’s new Nautilus500 and Zalman’s Reserator 1 Plus. Both are second generation kits, and while Zalman’s design is a refinement of the original Reserator, the Nautilus500 is all-new for Corsair. Each offers a different take on water cooling, as well. The Reserator targets low noise levels, while the Nautilus aims for ease of installation. But which kit is best for you? And perhaps more importantly, is either significantly superior to traditional air cooling? Let’s take a look.

Why water?
Before probing the two water coolers we’ll be looking at today, we should take a moment to address some of the motivations behind water cooling itself. After all, if traditional CPU coolers are capable of keeping even Intel’s toastiest of space heaters from melting, why bother with the tubes, fittings, water blocks, radiators, reservoirs, and additional costs associated with water cooling?

For the answer, we need to look no further than water’s thermal properties, specifically how its specific heat capacity and thermal conductivity compare to that of air. Those properties help determine a material’s suitability for cooling applications, and as it turns out, water is far superior to air. A substance’s specific heat capacity is the amount of energy required to change the temperature of one unit mass of the substance by one degree. Specific heat capacity is commonly expressed in joules per kilogram Kelvin, with higher values reflecting a greater capacity to absorb and retain heat. Here, water has a sizeable advantage—its specific heat capacity of 4.184 J/gK is more than four times higher than air’s 1.005 J/gK. Water looks even better when we consider thermal conductivity, which describes a material’s ability to conduct heat. Thermal conductivity is measured in watts per meter Kelvin, and again, higher values are better. Water’s 0.6062 W/mK thermal conductivity dwarfs that of air, whose thermal conductivity is only 0.0262 W/mK.

While much of water cooling’s appeal coasts on its comparatively attractive thermal properties, where that water flows can also affect system temperatures. Traditional processor coolers blow air around inside an enclosure, relying on exhaust fans or careful ducting to coax hot air from a system. Water cooling can be considerably more direct by using tubing to cleanly pipe water flow from a case. Radiators and reservoirs can be housed in external enclosures where heat transfer won’t warm a system’s internal components, ideally resulting in lower system temperatures. However, it’s important to note that system components can actually depend on the airflow generated by traditional coolers. Some motherboards rely on airflow generated by processor fans to cool voltage circuitry around the CPU socket, and select graphics cards require directed airflow over more than just the GPU.

Water’s ability to deliver better cooling performance than traditional air coolers has made it popular among overclockers looking to offset the higher temperatures that come along with mind-numbing clock speeds and core voltages. Overclockers aren’t the only ones benefiting, though. The relative efficiency of water cooling has also spawned designs for the quiet computing crowd. These solutions aim to maintain acceptable temperature levels with less forced airflow—and ideally less noise—than traditional air coolers.

In addition to focusing on either lower temperatures or lower noise levels, water cooling systems can also differ when it comes to their makeup. Some are complete kits that include all the necessary parts, fittings, reservoirs, and radiators, while others are custom systems built from individually selected components. We’ll be focusing on the former, since building a water cooling system from scratch is generally the domain of only the most seasoned water cooling enthusiasts.

Water cooling has a lot of potential, but there are a few liabilities to keep in mind. Conductivity is probably the most obvious issue, but thankfully it’s one that’s easily avoided. You see, pure water isn’t actually all that conductive. Tap water is, but only because of the minerals and other elements floating around in it. So, instead of using conductive household tap water in a water cooling system, most manufacturers recommend the use of distilled water. Distilled water is much purer than what comes out of the tap, making it less conductive, and also less likely to gum up a water cooling system’s internals. Distilled water is cheap, too. Unfortunately, the same can’t be said for water cooling systems. Water coolers can cost several times as much as even the most expensive air coolers, setting the bar of expectations rather high for their performance.

Paging Jules Verne

Of course, just because the Nautilus is built to be affordable and easy to install doesn’t mean that it can’t hold its own in the performance department. Corsair says the cooler can lower the temperature of AMD processors by close to 30%, a claim we’ll have to put to the test.

The heart of the Nautilus500 is an external unit that houses the cooler’s pump, radiator, and reservoir. This unit is a black plastic affair, so it’s not the most attractive PC accessory, especially for the living room. However, the flat black finish is at least visually unobtrusive—until you turn the Nautilus on. When powered, the strip of translucent plastic on the left-hand side of the unit’s face glows bright green. It’s a nice visual cue to let you know that things are running, but some folks might find it a little gaudy.

At first, I thought there might be more to the translucent plastic than green lighting, but there isn’t. Despite the fact that the strip is right next to the reservoir’s fill cap, which would seem like a good location for a translucent window that allowed users to monitor the system’s fluid level, it’s just a green light. At least it’s not ultra-bright, death-ray blue, I guess.

Flipping the Nautilus’ external unit reveals a radiator nestled behind a gaping hole in the base. The radiator is slightly recessed, and plastic feet provide an additional inch or so of clearance for air flow. You’ll want to be careful about poking around under the unit since the radiator isn’t protected by any kind of grill, though.

The Nautilus500 moves air across the radiator’s cooling fins with a 120mm fan that pushes up to 74.4CFM at its maximum speed of 1800 RPM. Users can also select a low fan speed setting that dramatically reduces the Nautilus’ noise levels at the expense of cooling performance.

That fan speed switch can be found around the rear alongside the unit’s power plug and its fluid intake and outlet ports. I’ll get to the power in a minute, but first, take a moment to note the fittings on the fluid ports. The fittings are designed to stop fluid flow when hoses are unplugged, so it’s easy to disconnect and reattach tubing without having to drain the system. They do tend to drip a little when the hoses are first removed, so you’ll want to keep a bit of paper towel handy when disassembling the system.

Water gets pumped through the system by a DC pump that pushes 350 liters per hour. There’s no high/low switch for the pump, which seems to run at full capacity at all times. Corsair says it’s a low-noise design, though. We’ll see just how loud it is in our noise level tests.

Interestingly, the Nautilus’ CPU block is attached to the system’s clear plastic tubing right out of the box. Ten feet of 0.5″-diameter tubing is included, with five feet running from each of the CPU block’s hose barbs.

The tubing is secured with metal clamps that sit tight and secure, although it should be possible to pry them off with a set of pliers. Otherwise, the CPU block is a relatively demure affair, with a black finish hiding its copper construction. Corsair also points out that the block uses Delphi’s microchannel surface technology, which improves cooling efficiency by increasing the surface area inside the CPU block to make greater contact with the liquid flowing through it.

Turning the CPU block on its side reveals a copper base that’s polished nice and smooth. It’s not quite a perfect mirror, but apart from some scuffing around the edges, our sample was free of blemishes and visible scratches.

Although Corsair doesn’t bundle the Nautilus500 with additional cooling blocks, the company does sell GPU and north bridge blocks that can be added to the system. An SLI block is also on the way for dual-GPU rigs, although cooling additional components will obviously temper the Nautilus’ effect on CPU temperatures. The Nautilus’ tubing is rather stiff, as well, and I can imagine routing it from a system’s processor to GPU to north bridge could get a little complicated within the confines of smaller ATX enclosures.

While you don’t get extra cooling blocks, Corsair does bundle the Nautilus with everything you’ll need for installation in systems with sockets 478, 754, 939, and 940, and LGA775. Corsair says a little gentle bending will adapt the existing mounting hardware to AM2, as well, but a proper AM2 bracket will be bundled with the Nautilus when the Socket AM2 becomes available.

In addition to socket mounting hardware, you also get a PCI slot cover with tubing cutouts and a power adapter. The Nautilus runs off power drawn from a four-pin Molex connector, and additional three-pin fan plugs are provided to allow the unit’s fan and pump speed to be monitored by motherboard fan headers. Finally, Corsair includes a bottle of its anti-corrosive COOL liquid additive, which the company recommends only be combined with distilled water.

Nautilus500 installation
Corsair claims the Nautilus500 can be installed in just over eight minutes, and while matching that time might take a little practice, installing the unit on our open test bench took just over 10 minutes. I tend to be pretty methodical, and I stopped a couple of times to double-check the instructions to ensure that this was really all I had to do to get everything up and running.

The installation process is surprisingly straightforward, and it all starts at the socket. There’s no need to remove the motherboard, as the Socket 939 bracket hooks right into a standard retention mechanism. Slap some paste on the processor, position the block in place, add a foam bumper, tighten one screw, and the CPU block is installed. It doesn’t get much easier than that, although if Corsair really wants to go all out in the ease of installation department, it might want to use a thumbscrew instead.

While Socket 939 is a snap, LGA775 installation is a little more involved. That’s not really Corsair’s fault, as the Intel socket’s four contact points require extra attention. Installing the Nautilus’ retention bracket is still relatively painless, and it can be done without removing the motherboard from a case. However, you will need to remove the motherboard if you want to replace the Nautilus500 CPU block with a different cooler, because the plastic clips that serve as mounting posts for the retention bracket can only be removed from the underside of the mobo.

Once the CPU block is installed, you’ll want to route the attached hosing through the case and into the outside world via the provided PCI slot cover. Tubing can be cut to size for a cleaner look or left at full length to allow for future expansion. Next, we cap the tubes with the included end plugs and plastic binders, both of which install within seconds.

With the CPU block installed and our tubing capped, we can connect everything and pop open the Nautilus’ reservoir. Corsair recommends that you first fill the reservoir with its COOL additive, and then top the system off with distilled water.

Since the Nautilus runs off a PC’s power supply, the system needs to be turned on for the pump to work. Unfortunately, you won’t actually have liquid running through the entire system, especially to the CPU block, until the pump starts running for the first time. That presents a potential predicament, since cooling performance will be significantly hampered until the pump has time to circulate liquid throughout. Fortunately, the circulation process doesn’t take long, and our Opteron 180 processor had no problem booting into Windows while liquid made its way to the water block. Just be sure to top off the reservoir with distilled water before closing everything up.

Once the system is running, it’s easy to tell whether the Nautilus500 is on. First, there’s the green light, which is pretty much impossible to miss. The external unit’s fan isn’t all that quiet, either, so you’ll hear it running, even with the low fan speed setting. Unfortunately, there’s no way to check whether liquid is flowing properly through the system. A motherboard fan header can be used to measure the pump speed, but it would be nice to have some confirmation of coolant levels and proper flow without having to fire up a hardware monitoring program.

Refining the slightly ridiculous

The secret to the Reserator’s silent operation is a massive radiator column that also serves as the system’s reservoir. This baby is huge, measuring six inches in diameter and nearly two feet tall. This time around, Zalman has toned down the aesthetics a little; the original’s radiator was anodized bright blue, but the Reserator 1 Plus is dressed in a more reserved black.

I’m a sucker for bold colors, so I actually didn’t mind the original Reserator’s blue hue. Still, the new black anodized finish should allow the Reserator to blend in better with its surroundings. There’s only so much blending a massive finned column of aluminum can do, though. The Reserator’s gargantuan proportions are difficult to disguise, and it’s tempting to simply give up on subtlety and showcase the radiator as a piece of industrial art rather than making an attempt at camouflage.

In addition to making the Reserator rather difficult to hide, the radiator’s size also makes it cumbersome to lug around. The radiator weighs over 14 pounds empty, and when filled with the 2.5 liters of liquid it can accommodate, it only gets heavier. You definitely don’t want this cooler attached to your LAN gaming rig unless you’re the one hosting the party.

The Reserator’s size and weight are necessary to allow the radiator to dissipate heat without the assistance of cooling fans. Natural convection requires loads of surface area, and you simply can’t get there with a smaller radiator. Such is the price of relative silence.

Although the Reserator’s radiator couldn’t be more different from that of the Nautilus500, both units use identical hose plugs. The quick-release plugs effectively block fluid flow when hoses are unplugged, allowing the radiator to be removed from the system for easier transportation. Such a maneuver was considerably more difficult with the original Reserator, whose compression fittings had to be backed up by separate hose clamps to cut off fluid flow.

The Reserator 1 Plus’s fluid flow is powered by a 5V pump that sits inside the base of the radiator tower. Like the original, the pump can push up to 300 liters per hour, which is slightly less than the flow rate of the Nautilus500. The Reserator 1 Plus also differs from the Nautilus when it comes to power. Rather than drawing juice from a PC’s power supply, it plugs directly into a wall socket. This prevents the unit from powering on automatically when the PC is booted, so you’ll have to remember to turn it on separately.

Those longing for a bit of the original Reserator blue will be pleased to note that the color makes an appearance in the brightly anodized CPU block. The block looks similar to the one shipped with the original Reserator, right down to the metal compression fittings and copper base. You’ll have to attach the hoses yourself, though.

Zalman ships the Reserator’s CPU block with the necessary mounting hardware for all modern CPU sockets, including Socket A. Those familiar with Zalman’s traditional air coolers will recognize a lot of this mounting hardware. Zalman tends to use the same mounting brackets for both its water and air coolers.

In addition to shipping the Reserator 1 Plus with a CPU block, Zalman also throws in a GPU block and eight memory heat sinks. Zalman sold this GPU block as a separate accessory for the original Reserator, so it’s nice to see it included in the box this time around.

The Reserator’s GPU block comes bundled with all the mounting hardware you’ll need, and it’s compatible with a wide variety graphics cards, including ATI’s and NVIDIA’s latest and greatest. Zalman even claims that it can handle the infamous GeForce FX 5800, which otherwise requires a Dustbuster to keep cool.

Sadly, the GPU block’s finish isn’t quite as shiny as that of the CPU block. The latter is polished to a near-mirror finish, while the former’s base is much duller and distinctly lacking in the copper department. That said, both are smooth, with nary a scratch to blemish either base.

Zalman rounds out the Reserator’s bundle with a collection of extra goodies, including a bottle of coolant additive, fittings to allow the system to be run with an auxiliary external pump, and an in-line flow indicator that visually confirms that liquid is flowing freely through the system. The flow indicator is particularly handy because the Reserator doesn’t make any audible noise when it’s on.

To connect all the Reserator’s bits and pieces together, Zalman ships the unit with 4 meters of blue silicone tubing. The tubing is more flexible than what’s included with the Nautilus, but the bright blue silicone detracts from the black radiator’s classy appearance. Zalman also makes a north bridge block that’s compatible with the Reserator, but doesn’t bundle it in the box. Liquid cooling of the north bridge is probably a little extreme for most folks, though, and adding it to the bundle would only push the Reserator’s price higher. As it stands, the unit is relatively expensive at close to $230 online. That’s certainly not unreasonable given the massive aluminum radiator tower and GPU cooler, but it might push the limits of some folks’ budgets.

Reserator 1 Plus installation
Zalman doesn’t make any bold claims about the Reserator 1 Plus’ ease of installation, and while you won’t break any speed records, setting everything up is pretty easy. Most of the installation time is spent cutting and fitting tubing between the system’s various components, with a total of four sections of tubing required to chain the Reserator, flow indicator, CPU block, and GPU block together.

Since it uses the same quick-release reservoir plugs as the Nautilus, you’ll find similar hose fittings included with the Reserator. While Corsair favors tool-free plastic binders to secure the hose fittings, the Reserator comes with metal clamps that all but require pliers for proper installation.

Tubing attaches to the Reserator’s CPU block with a pair of metal compression fittings. Tightening the compression fittings is easy enough, although you’ll probably want to grab a wrench to apply a little extra force on the last turn—the last thing you want is a leak at the CPU block.

Once the CPU block’s tubes are secured, installing the block is a relatively simple affair. It is necessary to remove the motherboard to secure Zalman’s retention bracket base plates for both Socket 939 and LGA775, though. That can add a significant amount of time to the installation process if you’re putting the Reserator in an existing system, although it’s not much of an inconvenience when building a new system from scratch.

Apart from requiring access to the underside of the motherboard, the Reserator’s CPU block mounting hardware is relatively simple to install. There are quite a few small parts to piece together, though, perhaps because Zalman shares the mounting hardware across several of its CPU coolers.

Installing the Reserator’s GPU water block adds more time to the build process, but it’s an extra component, so it doesn’t really count. It actually took me more time to remove our GeForce 7800 GTX’s stock cooler than it did to install the Zalman block and memory heat sinks, so you won’t be mucking around with the graphics card for long. The RAM sinks are particularly easy to install, as they’re equipped with double-sided thermal tape. Unfortunately, the tape’s only good for one application, so you’ll have to source your own thermal adhesive when it comes time for a graphics card upgrade.

Zalman recommends that the GPU block be installed after the CPU block, with fluid flowing first to the CPU, then to the GPU, then back to the radiator. Users who desire more focused CPU cooling can also run the Reserator without the GPU block if they so desire.

The final piece to the Reserator 1 Plus puzzle is the in-line flow indicator, which Zalman recommends be installed between the radiator’s outlet plug and the CPU block. Metal compression fittings make installation a breeze, although unlike the CPU block’s fittings, you can’t easily use a wrench to tighten things up.

Once all the blocks, fittings, and hoses are connected, one needs only to pop the radiator’s cap and fill it with a mixture of coolant additive and distilled water. Since the Reserator can be run independently of the PC to which it’s connected, it’s possible to circulate liquid through the system and top off the reservoir before booting.

Our testing methods
In addition to comparing the Nautilus500’s performance to that of the Reserator 1 Plus, we’ve also thrown a Zalman CNPS9500 LED into the mix. The CNPS9500 uses old-fashioned air to keep the CPU cool, but it’s one of the best air coolers on the market and should give us some interesting perspective on how Corsair and Zalman’s water cooler’s compare with more traditional CPU coolers.

All tests were run on an open test bench, using the following test system.

Thanks to Corsair for providing us with memory for our testing. 2GB of RAM seems to be the new standard for most folks, and Corsair hooked us up with some of its 1GB DIMMs for testing.

Our test systems were powered by OCZ PowerStream power supply units. The PowerStream was one of our Editor’s Choice winners in our latest PSU round-up.

We used the following versions of our test applications:

• Prime95 24.14
• rthdribl v1.2

The test systems’ Windows desktop was set at 1280×1024 in 32-bit color at an 85Hz screen refresh rate. Vertical refresh sync (vsync) was disabled for all tests. Most of the 3D gaming tests used the Medium detail image quality settings, with the exception that the resolution was set to 640×480 in 32-bit color.

All the tests and methods we employed are publicly available and reproducible. If you have questions about our methods, hit our forums to talk with us about them.

Noise levels
Noise levels were measured using an Extech Model 407727 Digital Sound Level meter. The reservoirs for each water cooler were located two feet from the motherboard, and the CNPS9500’s “reservoir” measurements were taken from the same location, two feet from the mobo.

We ran the Reserator with its GPU block installed and also with the block completely removed from the system. The Nautilus500 and CNPS9500 were tested with their high and low fan speed settings, with the motherboard’s fan speed control disabled for the CNPS9500.

Our motherboard noise level measurements show the Reserator out in the lead with a two to three decibel advantage over the Nautilus on its quietest setting. Using the Reserator’s GPU block knocks more than a decibel off of noise levels at this location, which isn’t too bad considering that the GeForce 7800 GTX’s stock cooler is reasonably quiet.

Interestingly, our Nautilus500’s high fan speed setting proves louder, even an inch from the motherboard, than the CNPS9500’s low fan speed setting. That’s particularly notable considering the fact that the Nautilus’ fan is two feet away. Nothing is louder at the motherboard than our air cooler cranking at full tilt, though. That’s to be expected given that neither water cooler has any active cooling elements near the CPU socket.

Moving our noise level tests to one inch from the reservoir presents an interesting problem: in half of the cases, noise levels were below 40 decibels, which is as quiet as our sound level meter registers. The Reserator’s pump is effectively silent, so the unit makes only the faintest of sounds, regardless of whether the GPU block is installed. The CNPS9500 dips below 40 decibels when we move two feet from the motherboard, too.

Unfortunately, while the Reserator’s reservoir/radiator unit is nearly silent, the Nautilus is quite loud. The unit’s low fan speed setting only knocks a couple of decibels off our noise level readings, and the low-frequency hum generated by the cooler is impossible to miss.

CPU temperatures
To examine cooling performance, we subjected the coolers to a brutal 15-hour torture test. We kicked things off with an hour of idling, followed by 12 hours under an intense load of two Prime95 maximum heat torture tests (one per CPU core) and one windowed instance of the “rthdribl” demo to stress the graphics card. After 12 hours under load, we left the systems at idle for a two-hour cool-down period. CPU temperatures were logged for the duration of the test, and Cool’n’Quiet was enabled.

We’ve averaged temperatures over the idle, load, and cooldown portions of the test, but before we get into that, we just had to bust out a graph charting CPU temperatures over the length of the testing session.

This graph tells us a few things that our averages won’t, namely how quickly temperatures ramp up and down with each cooler. Note that the Reserator’s CPU temperatures climb and fall much more slowly than the other coolers. CPU temperatures don’t actually peak with the Reserator until more than two hours after we begin the load portion of the test. They take longer to settle at idle, as well, with nearly two hours passing before each Reserator configuration settled at its stable idle temperature.

Apart from illustrating the speed of temperature change, the graph above makes it quite obvious which cooler offers lower CPU temperatures. The Nautilus may be loud, but it’s a much more effective cooler than either the Reserator or CNPS9500. The CNPS9500’s low fan speed setting looks particularly weak under our punishing load.

Breaking down our results into easier to manage averages paints a clearer picture of cooling performance at each stage of our torture test. The Nautilus’s high fan speed setting reigns supreme here, although the Reserator scores relatively well because it takes some time to warm up.

Under load, there’s simply no touching the Nautilus. Only a couple of degrees separates the unit’s high and low fan speed settings, as well, making us wonder whether Corsair could get away with an even lower fan speed setting that would hopefully produce much less noise.

The Reserator manages to come within seven degrees of the warmest Nautilus configuration, but only when its GPU block isn’t installed. Once the water block is running in the system, the Reserator’s CPU temperatures climb a full eight degrees. That’s still leaves the CPU cooler than it is with the CNPS9500, though.

Moving to cool-down, the Nautilus again outclasses the rest of the field. Its advantage isn’t as pronounced when our CPU is happily throttled at idle, but temperatures are clearly lower.

It’s interesting to note that during our two-hour cooldown period, the CNPS9500 actually registers a lower CPU temperature average than either Reserator configuration. The Reserator takes significantly longer than the others to cool down, especially when we throw the GPU block into the mix.

GPU temperatures
Our GPU temperature measurements were taken during the same torture test as the CPU temperature results. We’ve omitted the GPU temperature results for our CNPS9500 and Nautilus configurations as both used the stock GeForce 7800 GTX cooler and delivered equivalent GPU temperatures to our GPU block-less Reserator 1 Plus configuration.

The Reserator’s propensity for slow temperature changes carries over to GPU cooling, and it takes a while for the water-cooled GeForce 7800 GTX GPU to warm up and cool down.

Still, the Reserator’s GPU block manages to lower graphics chip temperatures across the board, despite the fact that water circulating through the block has already been warmed by the system’s CPU. Results like this make us wish Corsair had bundled its own GPU block with the Nautilus500.

Conclusions
Although both are all-in-one water cooling kits, Corsair’s Nautilus500 and Zalman’s Reserator 1 Plus couldn’t be more different. Where one falters, the other excels, and vice versa. That’s made for an interesting comparison, especially since the market for water cooling is diverse enough to accommodate both designs.

As was Corsair’s intention, the Nautilus500’s strength is easily its affordability and ease of installation. With a street price of just $150, the Nautilus is significantly more affordable than the Reserator, and snaps together with much less effort. More impressively, however, the Nautilus’ affordability hasn’t hurt its cooling performance. The unit delivers significantly lower CPU temperatures than the Reserator, making it a much better choice for overclockers looking to dissipate extra heat.

While the Nautilus’ affordability doesn’t impede its cooling performance, it does rear its head in the aesthetics department. The black plastic external radiator unit isn’t particularly attractive, especially next to the Reserator’s artfully machined aluminum tower. Dull visual appeal is a relatively minor issue when compared with the Nautilus’ noise levels, though. Even at the lowest fan speed setting, which still delivers stellar cooling performance, the Nautilus is loud enough that I wouldn’t want it in my living room. Those who crave silence should definitely stay away.

As it turns out, the Nautilus500’s greatest weakness is the Reserator 1 Plus’ strongest suit. Like its predecessor, the Reserator is barely audible, making it a boon for silent computing enthusiasts who want better cooling performance than quiet air coolers like the CNPS9500 can provide. The Reserator’s CPU temperatures weren’t nearly as spectacular as those of the Nautilus, though, so it’s definitely more appropriate for home theater PC projects than overclocked gaming rigs.

Of course, the Reserator’s relative silence doesn’t come cheap. The cooler sells for around $230 online, which will be enough to send some users into sticker shock. That’s not to say that the Reserator is overpriced. The additional cost is easily justified by extra features like the GPU block and flow indicator, and by the decadence that is the two-foot aluminum radiator tower. You won’t find any dull plastic here, just lots of machined aluminum and an exquisite anodized finish.

At the end of the day, which of these two water coolers is right for you depends entirely on what kind of system you intend to build. Home theater PC enthusiasts and anyone lusting after a quiet computing experience would do well to consider the Reserator 1 Plus, while overclockers on a budget and those seeking superior cooling performance would be much better off with a Nautilus500. That doesn’t answer the question of whether I’d actually use either over a much cheaper traditional air cooler like the CNPS9500, though. I would, but only in certain applications. Obviously, the Nautilus500 is far better suited to overclocking, and I’d gladly pay the premium for such a big drop in CPU temperatures. I’d also shell out for a Reserator 1 Plus for a silent home theater PC that mixed a little gaming with lots of background media encoding. The CNPS9500 may be quiet, but it’s not silent, and the high CPU temperatures we encountered with the low fan speed setting make me wary of subjecting it to extended loads.