Since the whole purpose of SilenX’s IXG-80HA2 is silence, I first checked out the noise level of the trio of fans in the three different modes. In “Low Speed” mode, the fans were totally silent, and running at what I’d estimate was less than 50%. In “Medium Speed” mode, the fans were also totally silent, and running at what I’d guess was 55-60%. At full speed, the fans are audible but far from annoying. My case has a lot of ventilation, but even then I could barely hear the fans with the side panel on. In a case with less openings, the fans at full speed would likely be barely noticeable.
I’d like to note that both adapters are designed by placing a resistor in series with the adapters’ “+” wires. During operation this resistor and the wire gets very hot, you’d probably want to let it cool some before touching it. I didn’t.
On most VGA coolers, with one fan blowing over much less fin surface area, changing the fan speed effects the GPU temperature very little, usually no more than a degree or so at idle, and a few degrees at load. With three fans, changing the fan speed affects the airflow three times as much, so I expected a significant change in temperatures running in the three fanspeed modes.
Idle temperatures were tested with the system sitting idle for 30 minutes. Load temperatures were tested by running Ozone3D’s FurMark, an OpenGL VGA benchmark that brings your GPU to 100% load by a graphic of a moving fuzzy doughnut. I ran the utility in “Stability Test” mode for 30 minutes. GPU temperatures were monitored through Asus Smart Doctor, the monitoring and overclocking utility that came with the video card.
First, though it wasn’t one of SilenX’s recommended applications, I tried running the IXG-80HA2 in passive mode. I found it kind of cool that both idle and load temps on the 9800GTX were exactly the same with the stock cooler as running the IXG-80HA2 passively. The only difference was that it took a very long time for the GPU to get back to idle temp after running at load, which is usually the case with passive cooling. I do have quite a bit of air moving in my case, besides the intake, outlet, and PSU fans, I have a pair of 120mm fans blowing through my liquid cooling radiator to the exterior of the case, so it is pretty likely that a less ventilated case would have different results running the cooler passively. Just to note, though the stock cooler normally is barely audible, when under load it ramps up to a loud, very annoying noise level.
At factory clock, we find the SilenX IXG-80HA2 is very effective at cooling down that hot GPU. A 29C difference with the fans at high speed is pretty incredible. Even with the fans at low speed, I got a 19C reduction in load temperature.
Next, I overclocked the 9800GTX from the factory overclock of 755mHz to a respectable overclock of 785mHz. I did not test the stock cooler at overclock due to the already high load temperature.
Overclocking the GPU really did heat things up, but the IXG-80HA2 still kept temperatures well under control in all modes. Overclock load temp in Low Fan mode was still 15C less than the stock cooler at factory clock load.