Thermaltake PW 850i ProWater Liquid-Cooling System Review

Today we are going to discuss one more mass liquid-cooling system – a universal, relatively compact and inexpensive, easy to assemble and work with and capable of coping with overclocked processors! Meet the new system from Thermaltake in our new review.

by Sergey Lepilov
09/03/2008 | 09:07 PM

During my overclocking career I have already tested over two dozens of mass-production liquid-cooling systems and only three of them turned out really worthy products. Unfortunately, these super-low “liquid-cooling systems yields” result from the manufacturers’ desire to make their solutions as simple and compact as possible. However, in this case they for some reason forget about the most important goal: to ensure high cooling efficiency at a low level of noise. Besides, note that the price of these solutions is often three pr even four times higher than that of a good air cooler that in most cases turns out more efficient and less noisy.


We would like to define what a mass-production liquid-cooling system should be like in order to successfully compete against monsters of air cooling? First, the radiator of such a system should be copper and should be able to accommodate at least two 120-mm fans, which means that in most cases it will have to be placed outside the system case. Second, the universal processor water block should also be all copper or with a clear acrylic lid over a copper base plate. Moreover, its internal structure shouldn’t be borrowed from the prehistoric water blocks of the very first liquid-cooling systems (there could at least be pins inside). Third, a system like that should come with a powerful but at the same time compact and quiet pump (Laing DDC, Mag, etc.) that can pump the liquid not only through the CPU water block, but also through the water blocks on the VGA card and mainboard chipset, if you decide to expand the system. Everything else, such as expansion tank, tubing, fittings, fans with adjustable rotation speed, decorative elements and other stuff is totally up to the manufacturer.

As you understand, even if the first three conditions are met, a liquid-cooling system like that will cost over ~$250, which limits its target user group dramatically. However, with components choices like that any liquid-cooling solution leaves no chance even to a super-efficient air-cooler. Remember Zalman Reserator XT, Koolance Exos-2 LX and Swiftech H20-220 Compact? Yes, only these three liquid-cooling systems proved more efficient than the best air-coolers.

Will our today’s hero, Thermaltake PW 850i ProWater, be able to become the fourth solution on this list? Out today’s review is going to see if it is efficient enough to meet overclockers’ needs.

Package and Accessories

A pretty big and heavy box features a convenient plastic carry handle. On the front of it there is a cut out window that reveals the major components of Thermaltake PW 850i ProWater:

The back of the box as well as its sides list all components of this liquid-cooling system and its technical detailed specifications:


There are two sections inside the box. Both of them are made of polyurethane foam and are shaped for specific system components. The first one is covered with clear plastic lid and contains the four major parts of Thermaltake PW 850i ProWater:

The second one contains a pipe, a bottle with coolant, a user’s guide and a box with small accessories. You can find the following among them:

I would like to draw your attention to the user’s manual booklet in several languages, which is very thoroughly put together:

As I have already mentioned, Thermaltake PW 850i ProWater comes with a bottle of coolant:


Note that it is not a coolant concentrate, like by other mainstream liquid-cooling solutions, but the ready-to-use cooling liquid, which doesn’t have to be diluted with anything. The plastic bottle is 500ml big. The main component of this coolant is propylene-glycol with anti-corrosion agents.

The last component included with the system is a flexible polyvinyl-chloride pipe 3m long with 9.5mm internal diameter:


Both, the pipe and the coolant, glow in UV light.

Now let’s take a closer look at the main components of Thermaltake PW 850i ProWater liquid-cooling system.

Design and Functionality

Radiator and Fan Block

First of all we have to dwell on the radiator and fan block. This unit measures 153 x 120 x 53mm and weighs ~450g:

The radiator is made of aluminum using DTT (Dimple Tube Technology). It implies that the internal sides of the radiator channels have special dents creating additional turbulence for the liquid flow. The previously tested Thermaltake BigWater 760i uses the exact same radiator:

There is a special retention on its back side that will hold the radiator on the case rear panel. Its sides are decorated with embossed company name:

There are two fittings covered with protective rubber caps at the bottom of the radiator:

There is a seven-blade 120 x 120 x 25mm fan fastened with screws on top of the radiator. It is covered with a wire grill. If you remove the grill and the fan, you will be able to take a closer look at the latter:


The fan of Thermaltake PW 850i ProWater uses a slide bearing with claimed MTBF of 30,000 hours (about 3.4 years of non-stop operation). The fan is made in China, its model number if TT-1225A and full marking reads A1225C12S, which means that it was most likely manufactured by Everflow Company:

According to the specifications, fan rotation speed may vary from ~1300RPM to ~2400RPM (±10%) generating 16-30dBA of noise. There is a rotation speed controller connected to this fan with a short cable:

It is not very convenient, because you will not be able to move the fan rotation speed controller outside the system case, so you will have to remove the case side panel every time you need to adjust the fan rotation speed. However, it will all depend on how often adjustment like that will be necessary. The remaining two cables are much longer. These are a power cable for the regular Molex-connector and a mainboard cable for rotation speed monitoring.

Pump and Expansion Tank

The second big part of Thermaltake PW 850i ProWater liquid-cooling system is the pump and expansion tank block:

These two irreplaceable parts of any liquid-cooling system are combined into a single block by Thermaltake PW 850i ProWater. The 350ml expansion tank is made of thick semi-transparent plastic. There are “Min” and “Max” marks for the coolant level on one of its sides. The filling hole at the top of the tank is covered with a screw-cap:

Two fittings also covered with protective rubber caps come out of the pump and tank:

Thermaltake PW 850i ProWater uses P501 pump (Thermaltake BigWater 760i uses P500 model):

However, they have pretty identical specs: water flow of 500 (±50) l/h, water lift of ~1.8m and power consumption of ~7.2W. According to the specifications, the claimed noise of the this pump is 16dBA and its ceramic bearing should last for 80,000 hours or more than 9 years of non-stop operation.

There are soft rubber pads stuck to the bottom of the expansion tank and pump:

They should be absorbing vibrations during work and thus reducing the level of generated noise.

CPU Water Block

The water block is made of copper, measures 58 x 58 x 25mm and weighs 336g. Its internal structure is unknown, because we couldn’t take it apart: its top part is soldered to the bottom.

There is a universal retention plate on top of the CPU water block. The internal diameter of the fittings also covered with rubber caps is 9.5mm:

The base finish is of remarkable quality. The surface is ideally even and impresses with impeccable mirror-shine:

Liquid Flow Control Module

The last part of Thermaltake PW 850i ProWater liquid-cooling system is the so-called flow control module (Flow TX). It is actually a piece of clear plastic tubing with a fan inside:

It allows to visually determine if the liquid is moving inside the system pipes or not. In my humble opinion, it is not a very useful device, because it simply creates additional resistance to the liquid flow.

Assembly and Installation Tips

Assembly and installation of Thermaltake PW 850i ProWater is simple and intuitive. You can download detailed instructions from the official web-site, but I am going to dwell only on the key steps. First of all we need to install the water block onto the mainboard. You will have to put four spindles into the holes around the processor socket and lock them with screw nuts and plastic washers (hereinafter we are going t use the installation procedure for the LGA 775 mainboard as an example):

The backplate with soft padding is installed on the bottom of the PCB:

Then place the water block on top of the CPU with a thin layer of pre-applied thermal compound and press it firmly with four large screw nuts:

The block is pressed extremely securely against the processor heat-spreader, so do not overdo it, because you may damage the board. As you can see on the photo above, the retention plate on the water block is pretty compact and doesn’t get in the way of any electronic components around the processor socket.

Then we need to install the radiator with a fan inside the system case:

All necessary screws are included among the bundled accessories. It requires a spot 153 x 120mm big to fit properly inside the system case. If the radiator with a fan does not fit into your case, Thermaltake made it possible to use it outside the case, but also on the rear panel. Therefore, there are special long screws among the bundled accessories. In this case you will have to turn the fan so that it could blow the air away from the radiator, instead of sucking the air into it. You will find the bracket for the case rear panel with special holes for the pipes and power cables in the accessories bundle, too.

And once the pump and expansion tank block has been placed conveniently inside the system case, all you need to do is connect all elements with pipes with clamps already in place on them. The completely installed system will look as follows:

In fact, Thermaltake recommends installing PW 850i ProWater system into large Full Tower cases, however, as you can see, the whole thing fit nicely into a pretty average ASUS ASCOT 6AR2-B (I haven’t used the drive chassis for ages). Once all the components have been connected and checked out you may use wire spirals that will prevent the pipes from bending. Moreover, you may also cut one of the connecting pipes in half and insert the flow control module between the two halves of the pipe.

The system is filled with coolant in at least two steps. First you fill the expansion tank and then turn on the system for a short while to pump the liquid through. Then you add more coolant to the tank to reach the maximum mark. The system you saw on the photo above consumed the entire 500ml bottle of coolant, therefore, you may want to look for an additional bottle later on or add distilled water.

That’s all. Nice and easy. As I have already said, the coolant and pipes should glow in the UV light.

Technical Specifications and Price

Technical specifications of the new Thermaltake PW 850i ProWater are summed up in the table below:

Testbed and Methods

Since the new Thermaltake PW 850i ProWater is designed to be used inside a system case, we tested it and its today’s competitor only inside a closed system case with the mainboard in vertical position.

Our testbed was identical for all testing participants and featured the following configuration:

All tests were performed under Windows XP Professional Edition SP3. SpeedFan 4.34 was used to monitor the temperature of the CPU and mainboard, reading it directly from the CPU core sensor and to monitor the rotation speed of the cooler fans:

The mainboard’s automatic fan speed management feature was disabled for the time of the tests in the mainboard BIOS. The CPU thermal throttling was controlled with the RightMark CPU Clock Utility version 2.35.0:

The CPU was heated up with OCCT (OverClock Checking Tool) version 2.0.0a in a 30-minute test with maximum CPU utilization, during which the system remained idle in the first 1 and last 4 minutes of the test:

I performed at least two cycles of tests and waited for approximately 20-25 minutes for the temperature inside the system case to stabilize during each test cycle. The stabilization period in an open testbed took about half the time. Despite the stabilization period, the result of the second test cycle was usually 0.5-1°C higher. The maximum temperature of the hottest CPU core of the four in the two test cycles was considered the final result (if the difference was no bigger than 1°C – otherwise the test was performed at least once again).

The ambient temperature was checked next to the system case with an electronic thermometer that allows monitoring the temperature changes over the past 6 hours. During our test session room temperatures varied between 26.0-26.5°C. It is used as a staring point on the temperature diagrams. Note that the fan rotation speeds as shown in the diagrams are the average readings reported by SpeedFan, and not the official claimed fan specifications.

The noise level of each cooler was measured according to our traditional method described in the previous articles with the help of an electronic noise meter – CENTER-321. The subjectively comfortable noise level was considered ~34.5dBA and is marked with a blue dotted line in the diagram. The ambient noise from the system case without the CPU cooler didn’t exceed 33.5dBA when measured at 1m distance.

We will be comparing Thermaltake PW 850i ProWater against the extremely efficient Thermalright SI-128 SE air cooler that sells for half the price of the liquid-cooling system. For the sake of fair experiment we used it with the same fan as the one on Thermaltake PW 850i ProWater radiator:

Since there are no holes on the fan frame (it has plastic spindles), we used a rubber band besides the traditional wire clips to hold the fan in place. We tested Thermalright SI-128 SE with the Thermaltake fan working in two modes: at minimal rotation speed of ~1310RPM and at maximum speed of ~2370RPM.

Well, let’s check out the results now.

Cooling Efficiency and Acoustic Performance

You may have already noticed that we are using two mainboards and two CPUs today. At first we were going to run all tests with two processors on the same Gigabyte GA-X38-DQ6 mainboard. However, for some reason this board wouldn’t start with the quad-core Intel Core 2 Extreme QX9650 processor, although they used to work perfectly fine together before. Therefore, we decided to test the liquid-cooling system and the air-cooler with a dual-core Intel Core 2 Duo E8400 on Gigabyte GA-X38-DQ6 mainboard and with a quad-core CPU on ASUSTek P5K Deluxe mainboard.

So, with the fan of Thermaltake PW 850i ProWater working at its slowest speed, we managed to overclock our dual-core processor to 4266MHz with 1.55V Vcore:

The quad-core processor overclocked to 3900MHz with 1.575V Vcore:

The results for both, the liquid-cooling system and its air competitor, are given on the chart below:

Thermaltake PW 850i ProWater copes pretty well with an overclocked dual-core processor, although it still loses to one of the today’s best super-coolers in both fan modes. However, the quad-core processor appeared an impossible nut to crack. Thermaltake PW 850i ProWater loses much more seriously to the air cooler. Besides, we couldn’t reach the maximum CPU frequency with this cooling system at all. Thermalright SI-128 SE won about 11ºC in quiet mode and at maximum fan rotation speed the gap reduces to 7ºC, which indicates that the radiator of the liquid-cooling system is pretty weak and cannot dissipate the heat efficiently enough.

Unfortunately, Thermaltake PW 850i ProWater turned out pretty noisy. At minimal fan rotation speed of ~1310RPM you can clearly hear the pump (35.9dBA/1m) even though the pump and expansion tank block was installed inside a closed system case with special noise insulation using soft polyurethane foam padding. If we had attached the pump to the bottom of the system case, as the guide recommended, the noise level could have been much higher. As for the maximum fan rotation speed of ~2370RPM, it is louder than the pump reaching an extremely uncomfortable level of 42.9dBA/1m.


As we learn more about the new Thermaltake PW 850i ProWater liquid-cooling system we realize that it doesn’t meet the minimal criteria for the efficient liquid-cooling system that we pointed out in the introduction. And the test session did prove that Thermaltake PW 850i ProWater may not be suitable for overclockers. Even though it is a relatively inexpensive liquid-cooling system, it can’t compete against much cheaper air-coolers.

Nevertheless, it does have a few indisputable advantages besides the price. Thermaltake PW 850i ProWater is a universal system supporting all contemporary platforms, it is easy to assemble and install and is pretty quiet at the minimal fan rotation speed.