Our test kit includes an ATI Radeon HD 5870 2GB Eyefinity 6 graphics card and an Intel Core i7-870 CPU, which has been overclocked from 2.93GHz to 3.4GHz using a vcore of 1.305V and a CPU PLL of 1.9V. This is a modest overclock, but our test kit will spend most of its life under high load, so pushing it too far isn't in anybody's interests. More importantly, some poorer-performing cases push the CPU temperature to above 80°C, so even this overclock will prove to be too much for some cases.
The CPU is cooled by a Gelid Tranquillo CPU cooler with a Noctua NF-S12B ULN 120mm fan. The NF-S12B ULN is a low-airflow fan, so it will highlight cases with poor cooling for the CPU. We also lock the fan speed on the graphics card to 30 per cent to prevent the automatic speed control interfering with the results.
We record the temperature of the CPU using RealTemp, noting the temperature of the hottest core, and using GPU-Z to log the temperature of the graphics card. Having recorded the ambient temperature in front of the main air intake of each case, we're then able to calculate the delta T - the difference between the ambient temperature of our lab and the temperature of the hardware. To load the system, we use a combination of the Canyon Flight benchmark in 3DMark06 and the smallfft test in Prime 95.
Intel Core i7-870 CPU overclocked to 3.4GHz
Graphics card: ATI Radeon HD 5870 2GB Eyefinity 6
Motherboard: Biostar TPower I55
RAM: 2 x 2GB OCZ 1,866MHz DDR3
Hard drive: 160GB Seagate Barracuda 7200.9
Heatsink: Gelid Tranquillo with a Noctua NF-S12B ULN fan