Optimizing Fan Technology For Less Noise
Then there’s the fan. Several different variables affect its performance. First, how fast is it spinning? The GeForce GTX 480 was a bit of a learning experience for Nvidia’s engineers. Just take a look at GeForce GTX 480 And 470: From Fermi And GF100 To Actual Cards! if you don’t remember how that played out. Without rehashing too much painful history, the board was both hot and loud. In the wake of the 480’s launch, Jen-Hsun and several other employees sat down and listened to various cards at different noise levels for weeks. In the process, Nvidia’s engineers settled on a 36 dB specification that later became the target ceiling for GeForce GTX 680.
Of course, getting there required an effective cooler, which is why product launches are often accompanied by talk of embedded heat pipe designs and, even more premium, vapor chambers that help cut temperatures by an additional eight to 12 degrees. If you assume five watts per degree Celsius, that’s up to 40 to 60 W of additional cooling at the same acoustic level. Take two competing GPUs rated for similar power, then, arm one with the more effective heat sink and deprive the other of comparable thermal performance. This comparison goes a long way in explaining my critique of acoustics in AMD Radeon HD 7970 GHz Edition Review: Give Me Back That Crown! Nvidia had to learn its lesson with GTX 480, which paved the way for a much less obtrusive 580. And the culmination of that work, which continued evolving after Fermi, is Titan’s sink.
Second, how are the fan blades and airflow interacting within the cooler? A cooling solution can be not loud, but still annoying. Even at idle, we’ve had cards in the lab that exhibited a high-pitched buzz or whooshing of air. The buzz often comes from the motor. And for Nvidia, avoiding it meant working closely with fan vendors on a spec that defined what the motor needed to do. Suppressing the whistling noise requires some optimization of the scroll at the bottom of the fan, and again, this is something that had to be researched, identified, and then engineered around. To the layperson this all sounds easy, but if it were, we wouldn’t feel so strongly about the discrepancy between some of the offending cards we've reviewed from both AMD and Nvidia.
Despite his team’s progress, Nvidia’s Bell says he’s not completely happy with Titan’s acoustics and wants to cut down on motor noise even more. The experience he’s going for is getting into your car and turning on the engine. There’s a massive fan in there that’s really loud as it pours air across the components under your hood. But it’s not an issue in the cabin, and the noise you do hear isn’t offensive. Of course, if you have a GeForce GTX Titan you also know that, while it ships with a conservative fan ramp, it can also be tuned more aggressively if you’re willing to tolerate more noise.