Our thermal readings come from a long loop of Metro Last Light, which is meant to stress the card with a demanding load and represent other 3D scenarios. This is a particularly taxing title, and it's possible that temperatures would even be lower in less intensive games.
|Model||Idle||Gaming Load |
|GeForce GTX 750 Ti Reference||28 °C||65 °C|
|GeForce GTX 750 Ti Passive||29 °C||80 °C|
|GeForce GTX 750 Ti Low Profile||29 °C||80 °C|
As with our passively-cooled GeForce GTX 750 Ti, this single-slot version with its small heat sink and fan is helped by Nvidia's 80 °C temperature target. Whenever the GPU hits 80 degrees, it gets throttled to make sure it doesn't exceed that value.
And here's where theory hits the real world, and the impact of throttling makes itself apparent. The chart with the GPU Boost clock rates will give us a better understanding of how frequencies correspond with frame rates later on.
Real-World Gaming Performance
So what do those numbers mean in reality? Even though Nvidia's GPU Boost clock rate falls by about 6.5%, measured frame rates only drop by 3.6%. In an average gamer's day, that's a negligible difference. A title that was previously playing back at 30 FPS falls close to 29; that's going to be hard to notice with your eyes.
As a result of Nvidia's thermal protection mechanism, though, you can really use whatever cooling solution you want. Just look at the reference GeForce GTX 780, 780 Ti, and Titan cards. They're able to run almost silently thanks to a capable design and GPU Boost's fast response.
First, we'll check noise under a couple of different workloads. Measurements are taken using a studio-quality microphone with the same calibration we use for our PC audio testing. The mic is positioned vertically in the center of the graphics card, 50 cm away.
|Model||Idle||Gaming Load (Open Test System)|
|GeForce GTX 750 Ti Reference||31.5 dB(A)||34.1 dB(A)|
|GeForce GTX 750 Ti Passive||N/A||N/A|
|GeForce GTX 750 Ti Low Profile||32.1 dB(A)||38.5 dB(A)|
At idle and under load, the single-slot cooler is louder than Nvidia's little reference-class orb-style cooler. However, the acoustic output is what we'd consider to be acceptable. The combination of a small heat sink and proactive thermal protection technology is certainly favorable to burning the card or running at higher clocks with obnoxious fan speeds.