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Cooling System

Besides, the card is equipped with an IceQ 4+ cooler that proves to be a copy of the reference cooler with a somewhat different blower.

The GPU heatsink and the metallic plate that cools the memory chips and the power components are the same as those of the reference heatsink:

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 because 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 2.20. 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 GC1 thermal grease.

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

There are a few important things that must be noted. First, the GPU frequency of the card is not reduced to 500MHz in 2D applications as on reference Radeon HD 4870. People at HIS seem to have forgotten about this power-saving capability of the chip when they pre-overclocked it. And second, the blower works at a very high speed and switches from one speed to another in a jump (the specific speed depends on the GPU temperature). As a result, the card is rather noisy while the sudden changes in the fan’s speed are annoying. The imperfect BIOS is a sad and serious fault of the company’s engineers.

So, I decided to finish the card’s BIOS off manually. Using Radeon BIOS Editor version 1.18 and the original BIOS of the HD 4870 IceQ 4+ Turbo (a 44.5KB WinRAR file), I reduced the GPU frequency in 2D mode from 770MHz to 250MHz and adjusted the GPU voltage from 1.263V to 1.083V. I also typed in the frequency of 500MHz for the UVD mode (video playback), just like on the reference Radeon HD 4870. Besides changing the frequencies and voltages, I also corrected the operation of the blower so that its speed varied smoothly depending on the GPU temperature (from 30 to 100°C).

 

As the result of my tweaking the card’s BIOS, the GPU temperature grew up by 2°C under load but the fan’s speed and noise lowered considerably.

The monitoring graph shows that the speed of the cooler’s fan now changes smoothly within a maximum of 2500rpm and a minimum of 1450-1500rpm (for 2D mode). You can download the edited BIOS, too (a 43.3KB WinRAR file). I want to warn you that if your BIOS update fails, neither I nor X-bit Labs won’t be responsible for the consequences. You can take a look at the graph below to see the temperature of the graphics card at the full speed of its fan (about 5300rpm).

Unfortunately, the card’s GPU proved to have low overclocking potential. I could only overclock it from its default 770MHz to 785MHz, i.e. less by 2% (+4.7% to the GPU frequency of the reference HD 4870). The memory chips did much better. I overclocked them from 4000MHz to 4600MHz (15% above the default frequency and 21.1% above the memory frequency of the reference HD 4870) without any instability or image artifacts.

The card’s temperature didn’t change much at the overclocked frequencies although the blower got about 200rpm faster and somewhat louder under load.

The last thing I want to add about the card is that its cooler is covered with ultraviolet-sensitive paint.

The HIS Radeon HD 4870 IceQ 4+ Turbo 1024MB sells at about $310 in retail whereas the recommended price of the Radeon HD 4870 512MB is $269.

 
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