Temperature, GPU Boost And Noise
Infrared Temperature Measurement
In order to get precise infrared thermal measurements, we’re using either a special tape or lacquer with known emissivity. The transparent paint, which is used by board manufacturers for so-called tropicalizing, is well-suited for analyzing the backs of PCBs (or other surfaces with unknown emissivity). The largest measurement errors occur when normal infrared thermometers, which invariably have dihedral angles too large to capture the VRM pins, are used. Doubly so if the emissivity can’t be set exactly.
This is why we’re using an Optris PI450, which doesn’t just provide us with high-resolution pictures in real time, but also allows us to define all measurement sites exactly.
We’re first observing the graphics card’s temperatures in a closed PC case (be quiet!'s Silent Base 800) while running a gaming loop. A limit of 83 degrees Celsius, which was set as the maximum temperature, is reached quickly, but only surpassed briefly before returning to the 82 to 83 degree Celsius range.
GPU Boost Frequency
If the frequency line is added to the temperature graph, then it’s easy to spot how the GPU Boost clock rate of 1215MHz (Titan X lands at 1190MHz) first takes a deep plunge and then slowly steps back up to 1189MHz (compared to Titan X's 1164MHz). It stabilizes there, except for some smaller drops attributable to minor load increases that threaten to push the card past its maximum temperature.
Temperatures after Prolonged Operation
As with the GeForce GTX Titan X before it, the 980 Ti lacks a backplate. This is for the best, really. While they do look good, it's far better for anyone planning an SLI configuration to leave extra room between cards for airflow. We’ve documented how the new card heats up and how heat spreads across the PCB in a 10-minute video.
The voltage transformers’ temperatures surpass those of the GPU after approximately 30 minutes.
Hot air is methodically pushed out the back. We measure 78 to 80 degrees Celsius where it leaves the graphics card, though this number fluctuates a bit.
The maximum fan speed is reached after nine minutes in the same closed PC case. After that, it remains constant unless the load decreases. Nvidia's cooler needs to keep the GeForce GTX 980 Ti at an 83-degree target and deal with 233W, which pushes its fan to approximately 2460 RPM.
As always, we use a high-quality microphone placed perpendicular to the center of the graphics card at a distance of 50 cm. The results are analyzed with Smaart 7. The ambient noise when our readings were recorded at night never rose above 26 dB(A). This was noted and accounted for separately during each measurement.
Let’s first take a look at the frequency spectrum resulting from the fan needing to keep Nvidia's GeForce GTX 980 Ti at 83 degrees Celsius during the gaming loop. The results are the same for the company's GeForce GTX Titan X. After all, both cards share the same cooling solution, and their fan speeds are identical as well.
We don’t measure any low motor noises, which we sometimes hear from the fans used by many of Nvidia's board partners. What we do hear is a pleasant whooshing sound spanning a relatively wide band of the spectrum. It starts right above two of the somewhat more pronounced areas (at 1.2 and 1.9kHz). Coil whine, which is usually found between 6 to 7kHz, is completely absent. The rest, from 10kHz upwards, is pure air movement.
The following table summarizes the situation a little differently. First, we ascertain fan speed in a closed case. That value is then dialed in manually on an open test bench. This way, we get around the fact that you just can’t measure a graphics card on its own in a closed case with the rest of the system running.
|Open Case (Test Bench)||Open Case (Fixed RPM, Case Simulation)||Closed Case (Full System)|
|Gaming Loop||44.3 db(A)||44.6 dB(A)||39.7 dB(A)|
Apart from the fact that Nvidia’s GeForce GTX 980 Ti can’t hold its maximum GPU Boost frequency over prolonged periods of time, the company's reference cooler is still the benchmark that all other direct heat exhaust (DHE) coolers are measured against. Nothing changes from the Titan X.