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The GPU of our Radeon HD 6850 Vapor-X was manufactured on the 14th week of 2011.

It incorporates 960 unified shader processors, 48 texture-mapping units and 32 raster operators. The GPU is pre-overclocked by 25 MHz to 800 MHz (+3.2%). This looks like very cautious factory overclocking to us.

We’ve got the same memory chips, totaling 1 gigabyte, as with the Sapphire Radeon HD 6870 DiRT 3 Edition.

The memory frequency is pre-overclocked 4400 MHz (+10% to the default level).

The card’s cooling system combines an evaporation chamber, heat pipes and slim aluminum fins. One 11-blade fan is set to blow at the whole arrangement.

There are three heat pipes, 8 mm in diameter, lying right on the evaporation chamber.

 

The pipes are supposed to cool the center of the copper base and transfer the heat to the heatsink fins whereas the chamber distributes the heat among the low-profile fins below the PWM-regulated fan. The next two diagrams show how efficient this design is:


Auto mode

Max RPM

In the automatic regulation mode of the fan (up to 2120 RPM) the GPU temperature reached 68°C. At the maximum speed of the fan (3690 RPM), the temperature was only 59°C. Now, what about the noise factor?

We measured the level of noise using an electronic noise-level meter CENTER-321 in a closed room about 20 sq. meters large. The noise-level meter was set on a tripod at a distance of 15 centimeters from the graphics card which was installed on an open testbed. The mainboard with the graphics card was placed at an edge of a desk on a foam-rubber tray.

The bottom limit of our noise-level meter is 29.8 dBA whereas the subjectively comfortable (not low, but comfortable) level of noise when measured from that distance is about 36 dBA. The speed of the graphics card’s fan was being adjusted by means of a controller that changed the supply voltage in steps of 0.5 V.

For the comparison’s sake, we’ve added the results of a Gigabyte GeForce GTX 560 Ultra Durable (GV-N56GOC-1GI), a reference AMD Radeon HD 6870 and an MSI Radeon HD 6950 Twin Frozr III into the following diagram and table:

Although the coolers of both Sapphire cards are quieter than the reference Radeon HD 6870 cooler, they are only really quiet in 2D applications at a fan speed of up to 1300 RPM. Take note that the Sapphire Radeon HD 6870 DiRT 3 Edition with its two fans turns out to be less noisy than the Sapphire Radeon HD 6850 Vapor-X which has only one fan. The Gigabyte GeForce GTX 560 Ultra Durable and MSI Radeon HD 6950 Twin Frozr III prove to be the quietest coolers in this comparison, although there can be even quieter solutions as you will learn from our next review.

Now let’s check out the overclocking potential of the Radeon HD 6850 Vapor-X. Our sample could work at the same clock rates as its cousin: 960/4800 MHz.

The temperature of the overclocked card increased to only 71°C at a fan speed of 2230 RPM.

 
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