With a digital thermometer we measured the temperature of several different spots on the video card (Radeon HD 4870 running at its default configuration) using the standard cooler and using Accelero Twin Turbo. We tested the reviewed unit under three scenarios: with the fans connected directly to the video card power plug (“PWM” column), directly to the power supply with it feeding the cooler with +7 V (“+7 V” column) and directly to the power supply with it feeding the cooler with +12 V (“+12 V” columns). During our tests room temperature was at 22º C (72º F) and we ran the Folding @ Home GPU client to make the video card to reach its maximum temperature. The results you can find in the table below.

Here is a brief explanation of the spots we placed the probe from our digital thermometer.

• Air output: It is the air output located on the rear of the PC, where the hot air produced by the video card exits the system.
• PCB: We installed the probe on the solder side from the video card printed circuit board on top of the UL white sticker that comes attached to the card.
• Heatsink: We placed the probe on the cooler’s heatsink.
• Memory: We placed the probe on top of one of the memory chips.
• GPU (back): We placed the probe on the PCB right behind where the GPU is soldered.
• Base: Here we tried to measure the GPU temperature. The problem was that putting the probe between the GPU and the cooler the video card wouldn’t turn on, because the probe was too thick and the GPU wouldn’t completely touch the cooler’s base, making it to overheat and activate the video card’s protection. So we installed the probe on the cooler’s base, on a location that it would allow the GPU to completely touch the base. This location was on top of the metallic frame that the GPU has around it.

As you can see Accelero Twin Turbo can in fact achieve a performance worst than ATI’s stock cooler if you connect it to the on-board power connector. Thus it is recommended that you connect this cooler directly to the power supply. At +12 V the performance was really impressive, with the GPU running 15º C cooler and with the memory running 12º C cooler. What really impressed us was the drop on the amount of heat being thrown out of the system, which decreased 26º C.