To quantify the noise these graphics cards produce, we used the Faber Acoustical SoundMeter application running on an iPhone 6S Plus. The meter was placed 18" from each graphics card while they were running the Unigine Heaven benchmark.
Since the Aorus card can stop its fans at idle, its noise levels are equal to those of the noise floor in our testing environment. The GTX 1080 Ti Founders Edition spins its fan at all times, so it makes a slightly discernable sound even with no load. Idle noise levels don't change whether these cards are overclocked or left at stock clocks, either.
Flip over to load noise levels, however, and the Aorus card sets itself apart in both stock and overclocked configurations. Left at factory clocks in gaming mode, the Aorus cooler runs more than seven dBA quieter than the Founders Edition card does—an impressive drop. Overclocked, the Aorus card still runs slightly quieter than Nvidia's reference design does at stock clocks. That's great performance, and it's what I've come to expect from Gigabyte's top-end coolers. Nvidia's Founders Edition cooler flirts with 50 dBA after the chip underneath is overclocked
Measured noise levels alone aren't the whole story with custom-cooled graphics cards, of course. The Aorus card is the third to cross my test bench with Gigabyte's 100-mm fan setup, and its spinners still sound great. Even under an overclocked load, the Aorus GTX 1080 Ti's primary noise character sounds like gently moving air. I suspect that part of the card's higher-than-expected noise levels come from the moderate coil whine it produces under load. This card's coil whine isn't the worst I've ever heard, but it can overshadow whatever gentle whoosh the fans make when they're running.
Nvidia's Founders Edition cooler can't hope to match the Aorus card's enormous heatsink for noise performance, and it doesn't. Even though its blower sounds quite good for this type of heatsink, the card still has a distinct growly character at idle, and it produces a rather high-pitched whine under load. The more piercing character of this sound is harder to ignore than that of the Aorus card's lower-pitched whoosh.
For fun, I also manually pushed each cooler's fans to 100% for noise-insensitive folks who are looking to get the most out of overclocking and GPU Boost 3.0. Even under those extreme conditions, the Aorus cooler didn't crest 52 dBA, and it still sounded quite pleasant at speed despite being noticeable in our testing environment.
The Founders Edition card produced a hair-dryer-like 62 dBA under the same conditions. To its credit, Nvidia's cooler sounds like nothing more than a hiss when it's maxed out, but it's way too loud and high-pitched a hiss to ignore. Folks in shared spaces or without closed headphones will want to steer clear of maxing out the Founders Edition's fan speed.
As we've come to expect after working with Pascal cards for a while, Nvidia's GPU Boost 3.0 makes the clock speeds marked on graphics card boxes more or less irrelevant to the delivered clocks one will get once a card is up and running. GPU core temperature is one of the major determinants of how GPU Boost 3.0 works, so we recorded temps while each card ran the Unigine Heaven demo.
At stock clocks, the Aorus cooler shaves a whopping 12° C off the Founders Edition card's result. At those temperatures, the card hung out around 1847 MHz to 1860 MHz in its "gaming mode," about 100 MHz higher than the reference card managed when I reviewed it. Flipping on the card's "OC mode" boosted clocks a bit further, to a range of about 1860 MHz to 1873 MHz in practice. In either case, the card is delivering over 100 MHz more than Gigabyte's specified clock speeds.
To get a rough idea of the power draw of the Aorus Xtreme Edition, we hooked up our testbed to our trusty Watts Up power meter and fired up Doom's Foundry level.
Under our test load, the Aorus GTX 1080 Ti only needs 10 more watts or so to deliver its superior performance. Once we start turning up the clocks, however, the tables turn. The GTX 1080 Ti Founders Edition consumes about 30 fewer watts when it's pushed to the sky, but that may be because of a power limit we discovered when both the core and memory are OCed. The Aorus card can sustain both core and memory overclocks without issue, so its higher power consumption comes with higher performance at all times. Whether you're running stock speeds or overclocking, however, a beefy power supply with a GTX 1080 Ti is a must.