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Corsair Nautilus 500: Water Cooling Goes Mainstream
Date: Feb 22, 2006
Author: Marco Chiappetta
Intro, Specifications & Bundle

Using water to cool the components in a PC was once considered and outlandish idea, and maybe even a little crazy. We all know what happens when water gets spilled onto something electronic, so why intentionally pump it into a system? Well, the short answer to that question is that water is far more effective at absorbing and removing heat than air. But the problem with using water is that it must be confined in a closed loop, like it is in most automobiles, and it cannot make direct contact with any exposed circuitry that has an electric current running through it.

This wasn't an insurmountable problem by any means, though. Once the idea of using water to cool a desktop PC caught on, hardcore modders went to work building custom water blocks and amassing the parts necessary to assemble water-cooled systems. In the early days, this was fairly difficult and pulling together all of the parts sometimes meant hitting up the local hardware store, auto parts dealer, and aquarium specialists. Not exactly the stores where you'd expect to purchase parts for a custom PC. But times have changed. There are now a myriad of reliable, high quality water cooling kits available from a number of well-known companies. Even Apple Computer has begun using a water cooling system on some of their top-of-the-line dual processor G5 Macs.

Generally speaking, water cooling a PC has quite a few advantages over air cooling, including lower noise levels and higher performance. However, there are some caveats to water cooling, like increased cost and the potential for leaks which could damage a system. Corsair, well known for their high-quality system memory, aims to tackled these problems, and play up the advantages of water cooling with the product we'll be looking at today, the Nautilus 500. The Nautilus 500 is a complete water cooling kit, compatible with the Intel and AMD platforms, that's affordable and easy to install. Take a look...


Corsair Nautilus 500 Liquid Cooling Kit
Specifications & Features
Water Pump Specification
  • Spherical Motor: Electronically commutated with brushless DC (direct current) design to minimize noise production and extend product life
  • Voltage Range: 8 to 13.2 VDC
  • Maximum system pressure: 22 PSI
  • Head pressure: 13.05 Feet (390 m/bar) @ 12 Volts
  • Maximum flow @ 12 Volts: 350 LPH (1.54 GPM)

Fan Specification (High Speed)

  • Voltage (VDC): 12
  • Current (Amp.): 0.3
  • Speed (RPM): 1800
  • Air Flow (CFM): 74.4
  • Pressure (mmAq): 3.2
CPU Block Specification
  • Supports Delphi Micro-Channel Technology
  • 100% solid copper construction for maximum heat absorption
  • Features one (1) 3/8. hose barbs
  • Supports Intel Pentium 4 (Socket 478 and LGA775) and AMD64 (Socket 754, 939, and 940) processor

Corsair's Nautilus Logo



Corsair bundles just about everything you'd need to install the Nautilus 500 into any Socket 478, LGA775, or Socket 939 / 940 / 754 based system, the only "accessory" you'll need to purchase separately is a jug of distilled water. Included in the box, we found one "COOL" water-block with 10' feet of food-grade clear tubing already attached to each of its barbs (inlet and outlet), retention brackets for all of the socket types we just mentioned, a small tube of thermal grease, two quick-connecting self-sealing connectors and two hose clamps. Noticably absent was an in-line flow indicator, but a quick glance at the back of the until will tell you if water is flowing out-of and in-to the unit properly.

Along with these items, Corsair also included a bottle of their "COOL" branded anti-corrosion / anti-algae water additive, a special power cable, a slot pass-through bracket, a fitted foam pad, and of course an installation manual that tells you what to do with all of these parts. Looking at the pictures above, it may seem like there are a lot of small parts to deal with when installing the Nautilus 500, but keep in mind that you'll only need to use one set of retention brackets depending on the type of socket in your system, and the self-sealing connectors and clamps only need to be installed once. The Nautilus 500 is actually incredibly easy to install; more on that a little later.

Inspecting the Hardware

With the exception of the water block, tubing, and power cables, the Nautilus 500 is a completely self-contained unit that incorporates a pump, reservoir, fan, fan controller, and radiator into one relatively small enclosure. The main unit is designed to sit on a desk or on top of a system, with the tubing running from the rear of the unit and into the computer.




The Nautilus 500's enclosure is made of a textured, black plastic and has only a few discernable external features. On the front of the unit, there is a small slot to one side that shows the level of liquid in the reservoir. Should you need to add some water, just above the slot is the metal reservoir cap. Simply remove the metal cap using a large flat-head screwdriver or a even a coin, and water can be poured right in. Also visible on the top of the unit is its integrated 120mm fan. The fan, which can operate at two different speeds, pulls air in through the radiator at the bottom of the unit, and exhausts it from the top.

On the rear of the Nautilus 500 is a switch, a four-pronged power connector, and a pair of quick connections for the tubing. The switch is a simple fan controller which makes the unit's fan run at a "high" or "low" speed. Low speed is for silent operation, while high speed is for high performance. Regardless of whether using high or low speed though, the Nautilus 500 is very quiet. The included power cable runs from the four-pronged connector to the notched slot cover plate, which then connects to any available 4-pin accessory connector coming from the system's power supply. There is no power switch on the Nautilus 500. It gets its power directly from the system's PSU and turns on automatically when the system is powered up. There is no need to manually to turn on the pump like there is with some other water cooling kits.

Installing the Nautilus 500


Corsair put a lot of thought into the Nautilus 500 kit in an effort to make the system as easy to install as possible. In fact, they made the Nautilus 500 so easy to install that it is the first complete water cooling kit we've seen that does not require the removal of the motherboard to mount the CPU water block. Many other kits require users to install a special bracket underneath the CPU socket to mount their water blocks, but the Nautilus 500 does not.

Before completely installing the Nautilus 500, we inspected, assembled, and built-up the kit to ensure that everything was functioning properly and that there were no leaks. Consider this step a necessity with any water cooling kit. The last thing you want to do is fully assemble and install a water cooling kit, only to find that the pump is dead or that it has a leak and is dripping water onto the components in your rig.


The radiator on the main unit's underside was in perfect shape, and because it is recessed slightly, it should be well protected from accidental dents or dings. The water block was in good shape as well. After removing a protective film, we found the water block to be very well polished. Upon close inspection, there were some minuscule swirl marks visible on the water block, but they are very minor. I ran the back of my fingernail over the water block a few times and can say that it is as smooth as glass.


The entire Nautilus 500 installation, not including the "leak test", took no more than 15 minutes. After inserting the quick connect fittings into the tubing and locking them into place with the included clamps, all that was left to do was connect the power cables, fill the reservoir, and mount the water block. We did not completely install the system into our test system's case, as you can see, but if we did, the only other additional step would be mounting the pass-through slot plate cover. To fill the system, we poured the included bottle of "COOL" additive into the reservoir, and then filled it the rest of the way up with distilled water. Then we powered-up the Nautilus 500 and as water began to travel though the tubing, we continually poured distilled water into the reservoir until the entire loop was completely filled. We then let the unit run for a while until all of the bubbles worked their way from the system. During this step, we found the included tubing to be somewhat rigid, but it softened up a bit once heated liquid circulated through the system for a while.


With the assembly and leak test complete, we then mounted the water block to our CPU. As we mentioned earlier, the Nautilus 500 can be installed on Socket 939 / 940 / 754, Socket 478, and LGA775 based systems without having to remove the motherboard from the case (Note: Uninstalling the kit requires the removal of the motherboard on LGA775 based systems).

For a Socket 939 system like the one pictured here, after applying a layer of thermal paste to the CPU, an "H" shaped piece of foam is slid over the water block between the tubes. Then, a similar shaped piece of metal gets placed over the foam, and the whole assembly gets mounted to the "stock" plastic Socket 939 cooler mounts by a single bar that runs down the center. A screw at one end of the bar gets tightened to lock everything tightly into place. The compression of the foam under the bracket is what forces the water block down onto the CPU.

On LGA775 systems, there are four plastic stand-offs that need to be inserted into the four "stock" mounting holes on those motherboards. Then, the shaped piece of foam is slid over the water block and after that, an "X" shaped bracket gets slid over the foam / water block, and the whole assembly is pressed down onto the four stand-offs until it is locked in place. The process is similar for Socket 478 based systems, but a larger metal plate, which looks like a larger "H" in the picture above, is used. That plate also locks into place on the stock plastic Socket 478 mounts.

The one thing common to all of the installation methods is the "H" shaped piece of foam that gets fitted between the mounting plates and water block. This single piece of foam is a key component to the kit. Should it lose its elasticity, or get ripped or damaged in any way, the water block will not sit correctly which will hinder the Nautilus 500's performance. Corsair claims the foam should last for quite a while, but should it need replacing for whatever reason, Corsair plans to keep them in-stock, and will replace them for users who send the company a request.

Thermal & Acoustic Performance

To assess the performance of the Nautilus 500, we dusted of an older Athlon 64 4000+ that was built using AMD's .13 micron manufacturing process. Newer AMD processors built on the company's .09 micron process run cooler and overclock higher, but we wanted to stress the Nautilus 500 with a hotter running (relatively speaking) CPU.

We'll be comparing the performance of the Nautilus 500, with its fan in "low" and "high" speed modes, to an all copper Thermaltake air cooler. We have two sets of numbers for you below. One set was recorded with our processor running at its default clock speed and core voltage (2.4GHz / 1.5v) and the other set was recorded with the processor overclocked to 2.7GHz with its core voltage set to 1.65v. Idle temperatures were recorded using Asus' PCProbe software, after letting the test system sit idle at the desktop for about 5 minutes. Load temperatures were recorded after letting the Folding@Home client run for approximately 15 minutes with the processor at a 100% load. Ambient room temperature was 22.2oC (72oF) throughout all of our testing.

Processor Temperatures with the Nautilus 500
Stock & Overclocked -- Idle & Load

At our processor's default clock speed, the Nautilus 500 was far more effective than the air cooler. At idle, the Nautilus 500 kept the CPU between 11 and 12 degrees cooler than the Thermaltake CL-P0075.  And with the processor running with a full load the Nautilus kept it between 8 and 9 degrees cooler. We noticed minimal differences in performance with the Nautilus 500's fan in low or high speed modes.

We pushed our CPU to its limits for our overclocked tests. With the air cooler installed, 2.7GHz was mostly stable, but the system did crash on us after running the Folding@Home client for an extended period of time. Not so with the Nautilus 500. With the Nautilus 500 installed, our CPU ran between 15 and 16 degrees cooler at idle, and 19 to 21 degrees cooler under load. 2.7GHz was completely stable after hours and hours of folding with the Nautilus 500. Please keep in mind, that not only will water cooling typically keep your CPU running cooler, but it may allow you to hit higher overclocked frequencies as well.

We also planned to give you some data using our trusty sound level meter, but we're happy to report that the Nautilus 500 was so quiet that out meter didn't register any sound from 1 ft. away. That's not to say the unit is completely silent, but it was too quiet to register on the meter. With the fan in low speed mode, there is no way you'd be able to hear the Nautilus 500 if it was placed under your desk. And with the fan in high speed mode, it was slightly louder, but still very quiet. A quiet running PSU or typical 7200 RPM hard drive will generate more noise than the Nautilus 500.

Our Summary & Conclusion

Performance Summary: Corsair's Nautilus 500 easily outperformed an aftermarket, all-copper air cooler. At stock and overclocked speeds, whether running at idle or with a full load, the Nautilus 500 kept the processor in our test system significantly cooler than the all-copper heatsink. The Nautilus 500 also remained very quiet throughout all of our testing whether its integrated fan was running in low or high speed modes.

Corsair has put together a very competent water cooling kit in the new Nautilus 500. It is very easy to assemble and install, it performed well, it's quiet, and with a $159 MSRP the Nautilus 500 is relatively inexpensive. Overall, we really liked the Corsair Nautilus 500, but we do have a few reservations and recommendations. Over time, most water blocks tend to get somewhat dirty, or clogged, or even in some cases corrode. Because the Nautilus' water block is completely sealed and doesn't have a see-through cover, you won't be able to detect any internal issues like these. This shouldn't be a problem if you follow the instructions and only use distilled water with the required additives, but it is something to keep in mind. We also would like to see the stand-offs necessary to install the kit in an LGA775 based system updated so that it's not necessary to remove the motherboard in order to uninstall the stand offs. As it stands now, you've got to squeeze the clips with a plier to fit them back through he mounting holes. We're also not too keen on the piece of foam that's used to transfer pressure from the retention brackets to the water block. We would have preferred some sort of metal spring or more durable piece of hardware, but the system did work perfectly in our testing. We can't comment on its long-term effectiveness, and whether or not the foam will lose its elasticity over time, but representatives from Corsair claim it should be fine. And in its current form, the Nautilus 500 worked perfectly.

In the end, the Nautilus 500 is exactly what Corsair says it should be. A high-performing, easy to install, affordable, water cooling kit. In the short time that we've had the Nautilus 500, we've found it to be easy to work with, and the silence it brought to our test system was a very welcome side effect. We really liked the Nautilus 500 and are giving it an 8 on the Heat Meter.

_Good Price
_Great Performance
_Adjustable Fan Speeds
_Easy Installation
_Near Universal Compatibility
_No Flow-Indicator
_LGA775 Stand-Offs
_Relatively Rigid Tubing
_No View into the water block


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