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Cooling System

Now let’s check out the cooling system. It is based on an aluminum heatsink consisting of thin ribs that hang on three 6mm nickel-plated copper heat pipes. The pipes are soldered to the copper plate of the cooler’s sole which is about 2 millimeters thick.

 

This heatsink contacts with the GPU only and is cooled with two fans installed in a plastic frame.

Note that the fans are different. The fan that cools the heatsinks right above the GPU has a diameter of 80 millimeters and nine blades. The second fan has a diameter of 70 millimeters and 11 slim blades. It cools the heatsink above the card’s power circuit and the power components themselves. Both fans are made by EverFlow and have the same speed (PWM-regulated).

The card’s temperature was measured in a simple test. I loaded it by running the Firefly Forest test from 3DMark06 at 1920x1200 with 16x anisotropic filtering for 10 times. I didn’t enable FSAA as the GPU load and temperature would have been lower then. The test was performed in a closed ASUS Ascot 6AR2-B system case (its fan configuration is described below in the Testbed and Methods section). The ambient temperature was 23.5°C. The card’s frequencies and temperature were monitored with RivaTuner 2.11. As I had dismantled the card before testing it, I replaced the thermal interface of the GPU with a thin layer of high-efficiency Gelid GCI thermal grease.

So, here are the results of the test with the card working in the Normal mode with automatic fan speed management.

As you can see, the GPU temperature is low in comparison with the reference cooler working in automatic mode. Take note that the fan speed is never higher than 1240rpm during the test! Of course, the card remains very quiet. You just can’t hear it against the noise from a quiet system case. Unfortunately, the sensors of the card’s power elements do not work (or are not installed) on the Palit Radeon HD 4870 Sonic. It would be interesting to know their temperature, too.

And now let’s see how effective the cooler is at the highest speed of the fans.

Well, I can just applaud Palit for equipping its graphics card with such an effective cooler. I should confess, however, that you may only want to run the card at the highest fan speed during a short benchmarking session or something because the level of noise is rather high then.

As opposed to the reference cooler which exhausts the hot air out of the system case, the cooler of the Palit card leaves most of the air inside the system case. Considering the high heat dissipation of the Radeon HD 4870, this will increase the overall temperature inside your computer.

So, I decided to set a subjectively comfortable speed of the fan, 1770rpm, and performed my overclockability test then. I found my sample of Palit Radeon HD 4870 Sonic to be stable and free from visual artifacts at a GPU frequency of 820MHz and an effective memory frequency of 4152MHz.

Frankly speaking, the core proved to have low overclocking potential. It didn’t reach 840-850MHz I had achieved with two Radeon HD 4870 cards from HIS. The memory chips overclocked better, but I think the memory frequency has but a small effect on the performance of a Radeon HD 4870.

Here is the card’s temperature at the overclocked frequencies:

After I had found the maximum frequencies of the card, I replaced its cooler with an Arctic Cooling Accelero Twin Turbo. And I found that under load the default cooler of the Palit Radeon HD 4870 Sonic was only 3°C inferior to one of the best coolers available (the fan speed of the Twin Turbo was set at 1770rpm, too). This test is yet another proof of the highest efficiency of Palit’s cooler.

One of the card’s BIOSes can be downloaded here (a 44.8KB WinRAR file). This card costs somewhat higher in retail than the recommended price of the Radeon HD 4870 512MB ($299), but I guess the extra 512 megabytes of graphics memory, the efficient cooler, the increased frequencies and dual BIOS are worth the difference.

 
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