Temperatures and Noise levels

Temperatures and Noise levels

After inserting the card in our system we can happily report, it's still working *phew*

The temperature stress test is as simple as it can be really. You can design all kinds of scenarios where you stress the card, but we pretty much look at the BFG GeForce GTX 285 before and after in terms of temperatures and DBa levels.

Now our BFG GTX 285 is an OCX edition, it's clocked faster at default at 712MHz on the core / 1620 on the shader and 1332 on the memory. What we'll be doing is what we always do to test a product; we stress it with FurMark which will really put strain on the GPU as it maxes out at a 100% stress level. It will heat up the GPU and voltage regulators badly.

Now this particular GTX 285 is rather noisy, thanks to it's higher clocks BFG had to increase the RPM levels of the ventilator matching it close to the noise level of the current GTX 480 really. As you can see we made things a little more daunting.

For the full load test we burn in the GPU for 5 minutes of Furmark and then take a temperature and DBa readings. Now the card with it's default BFG cooler shows idle temps of roughly 39 Degrees C and 76 Degrees C when it peaks.

We no look at temperatures with the Zalman cooler in three different modes

• LOW RMP = 33 Degrees C in IDLE and 63 Degrees C when the GPU is stressed 100%
• MED RMP = 33 Degrees C in IDLE and 59 Degrees C when the GPU is stressed 100%
• HIGH  RMP = 32 Degrees C in IDLE and 55 Degrees C when the GPU is stressed 100%

Quite honestly these are just really good temperatures, the cooler does as advertised. The card is nicely chilled down and depending on your preference anywhere in-between 55~63 Degrees C under full load.

But of course the different RPM fan modes have an effect on overall noise levels.

When graphics cards produce a lot of heat, usually that heat needs to be transported away from the hot core as fast as possible. Often you'll see massive active fan solutions that can indeed get rid of the heat, yet all the fans these days make the PC a noisy son of a gun. I'm doing a little try out today with noise monitoring, so basically the test we do is extremely subjective. We bought a certified dBA meter and will start measuring how many dBA originate from the PC. Why is this subjective you ask? Well, there is always noise in the background, from the streets, from the HD, PSU fan etc etc, so this is by a mile or two not a precise measurement. You could only achieve objective measurement in a sound test chamber.

The human hearing system has different sensitivities at different frequencies. This means that the perception of noise is not at all equal at every frequency. Noise with significant measured levels (in dB) at high or low frequencies will not be as annoying as it would be when its energy is concentrated in the middle frequencies. In other words, the measured noise levels in dB will not reflect the actual human perception of the loudness of the noise. That's why we measure the dBA level. A specific circuit is added to the sound level meter to correct its reading in regard to this concept. This reading is the noise level in dBA. The letter A is added to indicate the correction that was made in the measurement. Frequencies below 1kHz and above 6kHz are attenuated, where as frequencies between 1kHz and 6kHz are amplified by the A weighting.

How we measure. We measure in real-world conditions. We close the PC chassis and point our DBa gun it the chassis from a 75cm distance (you typically are 75~100cm away from your PC.

Here are the results:

Now since the fan RPM is fixed due to the Zalman fan controller the noise levels in both IDLE and LOAD will remain constant. At a medium RPM setting the noise level in IDLE and STRESS is rated at 40 DBa, not bad.

Overall pretty okay figures. At HIGH RPM mode the card is getting noisy though. But granted, if you need a little extra performance in an overclocking match, you can quickly shave off another 6~8 Degrees C with this mode.

With the temps in the low 60ies we recommend to keep the fan controller at a LOW setting though as that is a really good balance in-between temperatures and noise levels.