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Cooling System and Noise

Nvidia made an effort to improve its reference cooling system for the new flagship card considering the latter’s large GPU with increased heat dissipation. There are three key improvements mentioned by Nvidia: a vapor chamber, a heatsink with a large number of aluminum fins, and an advanced fan regulation system.

It is a daunting task to dismantle the Titan’s cooler as it is secured with lots of screws that vary in type.

So, the cooler is based on a metallic frame with thermal pads. This frame cools the memory chips and some power system components. Below the casing there is an aluminum heatsink with a vapor chamber.

 

It is secured on the GPU individually and has no contact with the other cooler components.

The cooler has a radial fan with a decorative plastic faceplate:

We couldn’t take the fan off since it seems to be glued to the metallic frame besides being fastened to it with three screws.

The cooler’s highlighting isn’t bright, but quite beautiful:

The cooler’s operation is based on the above-mentioned GPU Boost 2.0 technology and the GPU temperature limit of 80°C. The GPU’s clock rate depends on the temperature directly.

After the temperature limit is exceeded, the boost clock rate is lowered smoothly until it reaches the base clock rate of the GK110 chip. On reaching 105°C, the card triggers a protection mode, also known as throttling. Thus, the performance of the Titan’s GPU varies dynamically depending on its temperature.

You can lift the GPU temperature limit up to 94°C using the EVGA Precision X utility:

This will keep the Titan running longer at higher frequencies, but as soon as the new temperature limit is reached, the clock rate will go down again. Here’s a diagram from Nvidia illustrating the performance/temperature correlation of the Titan’s GPU:

The speed of the cooler’s fan is regulated in such a way as to keep the graphics card quiet until the GPU is 80°C hot. After that, the fan begins to accelerate.

As you can see, Nvidia emphasizes quietness over temperature, relying on the GPU’s protection mechanisms and GPU Boost 2.0.

If the temperature limit is shifted up, the cooler’s fan will work at higher speeds, ensuring stability.

To test the cooler efficiency we are going to use five consecutive runs of  a pretty resource-consuming Aliens vs. Predator (2010) game with the highest image quality settings in 2560x1440 resolution with 16x anisotropic filtering and MSAA 4x antialiasing. We used MSI Afterburner 3.0.0 beta 6 and GPU-Z 0.6.7 as monitoring tools. This test was performed inside a closed system case at 25°C room temperature.

So, let’s first take a look at the graphics card’s temperature at its default power and temperature limits. The fan is regulated automatically:

As you can see, the GPU quickly got as hot as 80°C during the first cycle of our gaming test. After that, the boost clock rate, which was 1006 MHz (yes, it was 1006 rather than 867 MHz), dropped first to 993 MHz and then to 876 MHz and finally to the base level of 837 MHz. In other words, if the GPU gets over 80°C hot, there is no talking about boost mode with the Titan. As for the speed of the fan, it rose from 1100 RPM to 2412 RPM and stayed at that level thereafter.

Now let’s try to raise the temperature limit to 94°C and set the power limit to 106%. The fan is still regulated automatically:

That’s quite a different picture! Upon reaching the peak 1006 MHz, our Titan only dropped its clock rate to 993 MHz and maintained it throughout most of the test. Of course, the Titan is going to deliver much higher performance now than at the noise-optimized standard settings. The top GPU temperature was 87°C during this test whereas the fan accelerated from 2412 to 2995 RPM.

Now we roll the temperature and power limits back to their defaults (80°C/100%) but set the fan at its maximum speed and rerun the test:

Everything’s simple here. The GPU is up to 70°C hot, always working in the boost mode at 1006 MHz. Now what if we increase the temperature and power limits to 94°C and 106% and use the fan at its maximum speed again? Let’s see.

There’s no difference in terms of clock rates but the top GPU temperature is 2°C higher at 72°C.

Summing everything up, we can say that it is highly important for the GeForce GTX Titan to be cooled properly if you want to have the GPU deliver its highest sustained performance in 3D applications.

We couldn’t measure the noise level of our GeForce GTX Titan because we either had to remove the casing (and obtain irrelevant results) or drill through the casing to access the fan connector. Neither option was appropriate for us, so we had to limit ourselves to our subjective impressions.

The card is absolutely silent in 2D mode, its fan working at 1100 RPM. It is very, very quiet indeed. In 3D mode the Titan is still comfortable enough at its default settings. The fan works smoothly when increasing or decreasing its speed. When the speed is higher than 2500 RPM, the GeForce GTX Titan becomes audible against the background noise of a quiet computer, yet remains quieter compared, for example, with the dual-processor GeForce GTX 690 or the reference AMD Radeon HD 7970. All in all, the cooling system is surprisingly not noisy for a graphics card with a TDP of 250 watts.

 
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