The four FCFBGA chips of GDDR5 memory are located on the face side of the PCB. They are manufactured by Hynix Semiconductor and have a total capacity of 1 gigabyte.
The chips are marked as H5GQ2H24MFRT2C, which means a rated clock rate of 5000 MHz and voltage of 1.5/1.35 volts. However, the memory frequency of the ASUS Radeon HD 6770 DirectCU Silent is only 4000 MHz, which is 800 MHz lower than written in AMD's Radeon HD 6770 specs. We don’t know the reason for the reduced memory clock rate, but there seem to be some overclocking potential here. The memory frequency is lowered to 1200 MHz in 2D applications whereas the memory bus is 128 bits wide.
Thus, the ASUS card has the following specs:
Now let’s move on to the most interesting thing about this product. We mean its cooling system, of course.
Really huge for such a modest card, the heatsink is based on four nickel-plated copper heat pipes with a diameter of 8 millimeters. Press-fitted on the pipes, the aluminum fins are 0.35 millimeters thick and placed 2.5 millimeters apart from each other. The whole arrangement is covered with a two-piece metallic casing.
It is likely that you can lower the GPU temperature by a couple of degrees by simply taking the casing off.
One more feature of this cooler is that it uses direct-touch technology. The only problem is that the Juniper GPU is a mere 170 sq. mm large, so it is only touched by the two central heat pipes.
The cooler seems to be overkill for such a modest graphics card. Let's check its performance out, though.
For our temperature test we run the Aliens vs. Predator (2010) benchmark in six cycles with maximum graphics quality settings at 1920x1080 with 16x anisotropic filtering. We use MSI Afterburner 2.2.0 Beta 7 and GPU-Z 0.5.5 as monitoring tools. This test is carried out with a closed system case at an ambient temperature of 24°C. The default thermal interface was replaced with Arctic MX-4 on each card tested for this review.
Here are the results of the ASUS Radeon HD 6770 DirectCU Silent:
The GPU is never hotter than 52°C at peak load and the card is absolutely silent. That’s just a perfect performance. Can this silent card be overclocked? Yes, it can. We boosted our sample to 960/5000 MHz.
The GPU temperature grew by a mere 4°C at that.
There's nothing better we could expect from that card, so let’s move on to the next one.