Temperature, Noise, Overclockability
You can learn how much power RV840-based products need from our Radeon HD 5770 review, but pre-overclocked graphics cards differ from reference samples in this respect. Moreover, AMD has updated the PowerPlay firmware and changed clock rates of some of the operation modes.
PowerColor's cooling system did very well despite the high ambient temperature during the test (30°C). The GPU of the reference card was as hot as 80°Cwhereas the PowerColor kept its GPU rather cold, within 54°C, notwithstanding the pre-overclocked frequency. We’ve only had a better result in this test with an MSI card which has a nonstandard cooler, too.
As for the noise factor, the PCS+ HD6770 Vortex II isn’t far from comfortable, yet audible in both 3D and 2D modes. Its sound is not irritating, but we have to admit PowerColor’s mistake here. When the card is idle, its driver sets the fan speed at 40% of the maximum, which means a noise level of 48.2 dB right next to the card. At the same time, the fan never accelerated above 50% of the maximum speed during our tests. So, the standard cooling system is 2 dB better and more comfortable subjectively.
The PowerColor card is equipped with a high-performance cooler but its high performance comes at the expense of noise. Let’s see how this affects the card’s overclockability.
Our PowerColor PCS+ HD6770 Vortex II could only be accelerated to a GPU clock rate of 950 MHz. We couldn't conquer the 1GHz peak and the card wasn't stable at the highest frequency we could set with the exclusive Overdrive tool. The memory subsystem did better and worked normally after a 9% increase in clock rate. So, the resulting frequencies were 950 MHz for the GPU and 1315 MHz for the memory chips. Not much of overclocking, you might say, but you should keep it in mind that the Radeon HD 6770 is actually meant to be clocked at 850 MHz!