Wednesday, December 22, 2010

Core i7 4 GHz Liquid Cooling 12 GB AMD HD6850 Corsair Force F60 SSD – HighPerformanceSystems

In this short article I´ll delve in the characteristics of one of the most afordable liquid cooling systems for high performance microprocessors, the Corsair H50. The test is done in a machine with a Core i7 930 processor clocked at 4 GHz with 12 GB DDR3 in triple channel, one Radeon HD6850 1 GB GDDR5 and a Corsair Force F60 SSD for the operating system, in this case Windows 7 Home Premium X64.

To begin with, I must say I’m not very enthusiastic about liquid cooling, since I see few advantages for an investment similar to a good tower type cooler with multiple heatpipes if we care properly of the heat flows inside the tower.

clip_image001Corsair H50 radiator in push-pull configuration.

The very unique advantage I see is the huge thermal inertia of water. Its temperature increase is rather slow due to its high specific heat of 4.18 kJ / (kg * K). Simply put, it takes many watts (J / s) to increase significantly the temperature of a small mass of water.

In this case the liquid cooling system is a compact Corsair H50 Hydro Series:

clip_image002The simple, factory pre-assembled and sealed, Corsair H50.

The most striking design characteristic of this water cooling kit is the water block (the part that makes contact with the processor).

The water block has a really great design and has a very high thermal performance. Its base is pure copper without any metal passivation (without zinc or nickel). This is the key to performance.

clip_image003Corsair H50 water block, pure copper.

Given the computer tower design, one Aerocool VS-9, plenty of ventilation holes, I had several options for radiator mounting. I have chosen to position it in the top rack and with the air intake from outside.

With this mounting I got the lowest temperatures (by far) on both full loading and idle.

clip_image004Aerocool VS-9 tower.

The fresh air intakes from the top panel, passes through the Corsair H50 radiator and is exhausted by the second fan inside the tower. The exhausted air, at idle and with a room temperature of 18º C outside the tower rises only 4º at 22° C and a peak of 39º C with a 100% load in Prime95 InPlace Round off Checking at 4 GHz.

clip_image005Push-pull configuration. Air entering through top panel.

In fact, thanks to this air inlet and another fan also placed in the front entrance, I achieve a positive pressure gradient that helps to dissipate the heat of the new AMD GPU:

The HD 6850 with 1 GB GDDR5 manufactured by ASUS

clip_image006AMD HD 6850 1GB GDDR5.

As you know the new AMD HD 6850 has one of the best price – performance of the whole GPU market.

clip_image00712 cm front fan in push configuration.

Thus, the cooling system of this machine is as follows:

  • One 12 cm front input fan.
  • One 12 cm rear output fan.
  • H50 Corsair Kit with two 12 cm fans in push-pull configuration at the top panel pushing air into the tower.
  • The power supply is mounted on the low panel with its fan intaking fresh air and expelling it through the back panel.
  • GPU: AMD HD 6850 1GB GDDR5 expelling air through the rear panel.

Final pressure balance inside the tower: positive (greater than outside atmospheric pressure). Provided that the system has a powerful GPU with high thermal emission is absolutely critical to obtain positive pressure. This will the push out the heat of the GPU naturally.

clip_image008System overview. On top of the DVD recorder you will appreciate the Corsair Force F60 SSD .

The operating system and the most used programs are installed in the SSD with his brutal performance in random accesses (up to 50000 IOPS), leaving a conventional 2 TB hard disk for data (suitable for mostly sequential workloads).

clip_image009Corsair H50, controlled temperatures and low noise.

Thus the CPU temperature at idle is approximately 6 to 8º C lower than the same system with a Scythe Yasya with two fans in push-pull. In load we have the following behavior:

At the very beginning of the stress test execution (Prime 95 InPlace Round off Checking) we face a very positive surprise with temperatures 12 to 15º C lower than with a high-end tower cooler.

This is because the water temperature should be around 28 to 32º C at this moment. Thanks to the large thermal inertia of H2O we have a few minutes of surprisingly low temperatures...

clip_image010Corsair H50 Water Block and the AMD 6850.

As time passes, coolant temperature goes up and we get increasingly higher temperatures. After about 60 - 80 minutes of test we reach a temperature plateau which is stabilized at 70 º C with transitory peaks of 72º C. The radiator exhaust air is around 39º C (18º C Outdoor temp).

With a Scythe Yasya with two 12 cm fans in push-pull I get 76 º C (absolute peak after 6 h) under the same conditions. They are also entirely satisfactory temperatures at these frequencies and such high load.

clip_image011Excellent results for the Corsair H50.

Also I want to emphasize the rather imperceptible noise level of the water pump in the Corsair H50. It rotates at around 1200 - 1500 rpm and its behavior is entirely satisfactory.

Conclusions:

I must admit, the Corsair H50 has changed in many ways my opinion about liquid cooling at low prices. Its superb thermal design and lower or comparable temperatures than state-of-the-art heatpipe air tower coolers has earned my respect and admiration for a very good piece of engineering.

In short, a great and compact design with the best performance for its price as long as it’s mounted the right way.

All photographs were taken with an excelent FujiFilm FinePix HS10.

Link to my original post in Spanish at ProfessionalSAT from Dec 15 2010.

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