Idle temperatures were attained by reading GPU-Z 0.3.1, EVGA Precision Tool as well as checking a third time with EVEREST Ultimate. After a restart of the PC, I allowed around ten to fifteen minutes for the PC to get sorted and allow the cooler time to stabilize. Load testing was done with the use of oZone3D.net's FurMark build 1.6.0 to stress the cards for a 20 minute testing cycle. Temperatures were again taken with the three previously mentioned applications.
It's worth mentioning is that all three programs when tested showed the same exact temperature with no variation between the three. Keeping the room at a constant ambient temperature is a little tough to do, but all of my testing was done with a 25 -26° Celsius environment, with slight fluctuations. I did, however, let the room stabilize before running the next testing series.
You can see I ran a series of testing here to give a better idea of its potential. I based all temperature comparisons off of the stock BIOS and fans ability to cool as to the IXG-80HA2. The ZOTAC stock cooler with stock GPU clocks of 675 / 1100 / 1688 (Core/Mem/Shaders) did an average job of cooling, idling at 60° and loading at 81° Celsius. SilenX shows that my 9800GTX is recommended to run on one fan, but I continued to test it with all three fan solutions.
As you can see, the cooler responds well to the addition of extra fans, finishing out with the coolest temperatures being attained with the three fan application. This set-up left me with an idle temperature of 38° and loading at 67° Celsius. Lastly, these numbers were recorded using the fans running at max flow and RPM's. These are the best results I was able to achieve at these settings.
This time I let the 9800GTX loose on just the core and shaders, keeping the RAM at the same speed as my vRAM doesn't overclock that well anyways. The overclocked settings were set at 750 / 1100 / 1876 (Core/Mem/Shaders). As you can see, the stock cooler BIOS kept the cooler within a few degrees of the non-overclocked temperatures, but I did like the improvements the multi-fan setups on the IXG-80HA2 offers.
While my best load temps were recorded during the dual fan setup, the tri-fan setup kept a lower idle temperature of 38° Celsius while loading two degrees higher than the dual fan setup at 77° Celsius. I can only attribute these findings to possible turbulence caused on this specific card with the tri-fans running at full speed.
I couldn't really get an audio reading on the fans with our dB meter, as the case I happened to have it in wasn't the most conducive case to getting the near silent atmosphere needed to get correct figures. I will say this; the fans are definitely audible, but not in any way what I would consider loud. With the addition of more fans as per your needs for your application, the noise does of course become a bit more noticeable. Again, testing of the fans efficiency to cool was done so the voltage was as good as it could be to supply these fans with everything they needed to do their job. I did not place the resisters inline during testing, but did just to see if they functioned. They do slow the fans down in two different steps, but this also lowers the coolers ability to do its job as well.