|PowerColor Radeon HD 6870 PCS+ Video Card|
|Reviews - Featured Reviews: Video Cards|
|Written by Bruce Normann|
|Tuesday, 11 January 2011|
Page 17 of 20
PowerColor PCS+ HD 6870 Temperatures
It's hard to know exactly when the first video card got overclocked, and by whom. What we do know is that it's hard to imagine a computer enthusiast or gamer today that doesn't overclock their hardware. Of course, not every video card has the head room. Some products run so hot that they can't suffer any higher temperatures than they generate straight from the factory. This is why we measure the operating temperature of the video card products we test.
To begin testing, I use GPU-Z to measure the temperature at idle as reported by the GPU. Next I use FurMark 1.8.2 to generate maximum thermal load and record GPU temperatures at high-power 3D mode. The ambient room temperature remained stable at 24C throughout testing. I have a ton of airflow into the video card section of my benchmarking case, with a 200mm side fan blowing directly inward, so that helps alleviate any high ambient temps.
The PowerColor PCS+ HD6870 1GB GDDR5 video card recorded 36C in idle mode, and increased to 82C after 30 minutes of stability testing in full 3D mode, at 1920x1200 resolution, and the maximum MSAA setting of 8X. With the fan set on Automatic, the speed rose to a meager 38% under full load. The idle fan speed is a very low 20%, which is too low in my opinion, especially since the axial fan is pretty much inaudible at the higher settings. I then did a run with manual fan control and 80 - 100% fan speed. I was rewarded by a modest increase in fan noise and a reduced load temperature of 69 - 71C.
82C is not a very good result for temperature stress testing, and it is a direct result of the manufacturer's decision to keep the fan speeds artificially low. I've become used to seeing video card manufacturers keeping the fan speeds low, especially with radial blower wheels that make a racket at higher speeds, but with a single axial fan there's really no point to doing that. You can knock 10+ degrees off the load temps by running the fan higher, which is what I recommend. Heat kills electronic components, and there's no joy in assisted suicide for your video card, plus the increase in noise is not too bad at full tilt. Most users will want to make custom software profiles to optimize the fan speeds for this non-reference design.
Load temps got up to a maximum of 76C when running continuous gaming benchmarks, with automatic fan speeds ramping up to 35% with the most challenging titles. This is fairly close to stress-test-maximums, so despite all the industry protests about using an extreme tool like FurMark for stress testing, it's doing a good job of emulating a real-world graphics load, IMHO. That temperature is higher than I like to see, but the chip can obviously take it. It's all the other components that I worry about.
FurMark is an OpenGL benchmark that heavily stresses and overheats the graphics card with fur rendering. The benchmark offers several options allowing the user to tweak the rendering: fullscreen / windowed mode, MSAA selection, window size, duration. The benchmark also includes a GPU Burner mode (stability test). FurMark requires an OpenGL 2.0 compliant graphics card with lot of GPU power!
FurMark does do two things extremely well: drive the thermal output of any graphics processor higher than any other application or video game, and it does so with consistency every time. While FurMark is not a true benchmark tool for comparing different video cards, it still works well to compare one product against itself using different drivers or clock speeds, or testing the stability of a GPU, as it raises the temperatures higher than any program. But in the end, it's a rather limited tool.
In our next section, we discuss electrical power consumption and learn how well (or poorly) each video card will impact your utility bill...