Temperatures & overclocking
Temperature musings
We perform our testing on an open test-bed with a 120mm fan simulating case airflow.
| Graphics cards | PowerColor PCS+ 4850 HD4850 512MB GDDR3 | Sapphire HD 4850 TOXIC 512MB | HIS HD 4850 IceQ4 TurboX 512MB | Force3D HD 4870 512MB | eVGA GTX 260 FTW 896MB | Leadtek 9800 GTX+ 512MB | Inno3D 9800 GT iChiLL 512MB |
|---|---|---|---|---|---|---|---|
| Ambient temperature | 22°C | 22°C | 22°C | 23.5°C | 23°C | 23.5°C | 24°C |
| Idle temperature | 53.5°C | 41°C | 46°C | 78°C | 53°C | 53°C | 48°C |
| Load temperature | 73.5°C | 65°C | 58°C | 90°C | 71°C | 67°C | 61°C |
| Ambient-to-load delta | 52°C | 43°C | 36°C | 67°C | 48°C | 44°C | 37°C |
Although not shown here (purely to avoid the chart getting too complicated), the ZEROtherm cooler on the PowerColor performs somewhat better than the AMD reference cooler, however when compared to the competition it looks decidedly lacklustre, coming in last place in terms of performance against Sapphire's Zalman-supplied cooler and HIS's IceQ4.
That said, the cooler still does a good enough job, and if you're willing to sacrifice some cooling performance in favour of noise, the ZEROtherm on the PowerColor PCS is the best of the bunch in that regard.
Overclocking
With the weakest cooling performance of all the
pre-overclocked HD
4850s we've currently tested, its no surprise to find that trying to
push the clocks even further wasn't a great success.
A modest increase of just 27MHz (+4%) on the GPU, and 28MHz (56MHz
effective) on the memory isn't going to shatter any records. With these
raised clocks the average fps in ET:QW at 1,920x1,200 4xAA 16xAF, went
from 54.17fps
to a surprising 59.43 FPS. This implies that not only did the
memory-clock increase provide a healthy boost to performance, but the
GPU
clocks also, resulting in an overall increase of around nine
percent.
