Clock Rates, Cooling, And Noise
Manufacturers can claim whatever they want in their marketing material. Actually achievable clock rates are subject to a number of hard-to-control variables, though. GPU quality, for instance, plays a big role, and there's no way to pre-screen what you get on that front. So, it's absolutely possible that a nominally slower card made by one board partner ends up faster than a more aggressively-tuned model from another partner. As a result, comparisons between products have to be approached with an understanding of some inherent uncertainty.
Board vendors can, however, control the settings and environmental factors that affect how GPU Boost ultimately determines operating frequency, depending on the situations it encounters. Beyond specifications like the power target or clock offset, temperature under load is perhaps the most influential factor in defining sustainable performance.
For MSI's GeForce GTX 1080 Ti Gaming X 11G, we measured an initial GPU Boost frequency of 1961 MHz. As the card warmed up, it maintained an average of 1873 MHz during our 30-minute measurement. But if the cooling were manually adjusted to more aggressive settings, this card would likely sustain the 1924 MHz peak reading we observed after warming it up.
Of course, the card does tolerate some additional overclocking. In our case, we achieved a stable 2050 MHz under air cooling, though we did have to significantly adjust MSI's fan curve to bring temperatures down. This results in a lot of extra noise you might not want.
If you plan to overclock, definitely consider increasing the power target to 330W and max out the voltage slider. As long as your temperatures stay under 149°F (65°C) during gaming workloads, 2050 MHz should be attainable aside from the occasional dip.
Getting a good overclock from your memory requires perseverance and a bit of luck. Seemingly stable settings might work short-term, and then prove dicey after a few hours of gaming. In the case of our sample, an extra 300 to 400 MT/s was feasible. Beyond that, performance started sliding the other direction.
Let's get back to our comments on the cooling frame covering the memory modules and their power supply. If we take our measurements on a free-breathing open test bench, everything looks good.
But if the conditions worsen (and they will in a closed case), MSI's GeForce GTX 1080 Ti Gaming X 11G starts showing signs of thermal stress. The memory's poorly-cooled VRM causes a small hot-spot that, over time, may have a negative impact on the GDDR5X temperatures.
At least for now, we'll signal the all-clear. According to Micron's specifications, the modules are fine at up to 203°F (95°C).
The situation worsens a bit under our stress test, since the card is getting quite a bit hotter (even on the open test bench).
Running a stress test inside of a closed case sends our readings into the critical range. Despite two good case fans, some of the memory modules are running outside of their specs. The PCB material around the hot-spot may suffer long-term effects as well. While it's true that FurMark isn't an application many enthusiasts run for fun, rendering and compute tasks can be similarly taxing.
Fan Speeds and Noise
Since MSI likes to emphasize quiet operation, the results we collect aren't surprising. Under a gaming load, the GeForce GTX 1080 Ti Gaming X 11G's fans spin at just over 1500 RPM on our open test bench. In a more realistic closed case scenario, they operate at 1800 RPM. Those results aren't exactly loud, but they are certainly audible.
We measured similar fan speeds during the stress test, with similar consequences.
Using our special temperature-controlled anechoic chamber, we took a maximum reading of 37.2 dB(A), which really isn't bad for a flagship 300W card.
This is one of the better interpretations of Nvidia's GeForce GTX 1080 Ti. Only the small slip-up in cooling the memory's power supply mars an otherwise strong performance. We're a picky bunch, though.
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