Power Consumption, Noise, Temperature, Overclockability and Compatibility
We already published information about the power consumption of ATI’s Radeon HD 3870 and 3850 cards in our reviews but we think it proper to publish it again to compare the parameters of RV670-based cards with their G94-based competitors from Nvidia. Our tests showed no difference in the power consumption of Gigabyte’s cards and the reference versions of Radeon HD 3870 and 3850.
The junior GV-RX385256H is competitive against the Nvidia GeForce 9600 GT in peak power consumption while the senior GV-RX387512H needs considerably more. But thanks to PowerPlay technology both cards are superior to Nvidia’s solution under low loads.
Both Gigabyte cards are equipped with the Zalman VF700-AlCu cooler and their noise parameters should be identical. We checked this out with a digital sound-level meter Velleman DVM1326 using A-curve weighing. The level of ambient noise in our lab was 36dBA and the level of noise at a distance of 1 meter from the working testbed with a passively cooled graphics card inside was 43dBA. Here are the results:
Alas, the cards are not noiseless. The cooler’s fan is always working at its maximum speed irrespective of the GPU load or temperature. This noise is perfectly audible among the other components of a working PC and you cannot lower it unless you use your soldering iron. The original VF700-AlCu comes with a FanMate controller, but the fan is connected right to the PCB here. On the other hand, the noise at a distance of 1 meter is not as high as to require an immediate action to reduce it. Gigabyte’s cards are about as noisy as the reference Radeon HD 3870 and GeForce 8800 GT.
The cooler is highly efficient, though. The GPU temperature is never higher than 52°C on the GV-RX385256H and 55°C on the GV-RX387512H even under continuous load. This is a better performance than what the reference GeForce 9600 GT cooler can do (60-62°C). And as for the GeForce 8800 GT, its GPU temperature can be as high as 80°C and more. Thus, we think the Zalman cooler is okay. Its highest performance makes up for its increased level of noise.
The cooler could not but affect the cards’ overclockability. We managed to raise the GPU frequency of the GV-RX387512H card by 100MHz from the default 775MHz to 875MHz. The memory chips could be overclocked to 1130 (2260) MHz, which was quite an achievement for chips with a rated frequency of 1000 (2000) MHz. The card was stable at these clock rates and easily passed the full cycle of tests.
The GV-RX385256H had more modest results at overclocking: 820MHz GPU and 800 (1600) MHz memory. That’s not a surprise really because this card uses samples of RV670 that have not passed the frequency check for the use on ATI Radeon HD 3870. Moreover, Gigabyte installs slow memory on it, with a rated frequency of only 700 (1400) MHz. As a result, we didn’t achieve the memory frequency of the reference Radeon HD 3850, which is 830 (1660) MHz. This product can hardly be interesting to overclockers.
We found no compatibility issues between the Gigabyte cards and mainboards supporting PCI Express standards earlier than 2.0 which is due to the implementation of PCI Express 2.0 support in the ATI RV670. All RV670-based cards start up in PCI Express 1.0 mode and enable the faster data-transfer mode only after checking the bus out for its compliance with PCI Express 2.0. This is a better approach than in Nvidia’s solutions. Nvidia’s early G92-based cards would often refuse to start up on some PCI Express 1.0a mainboards.