4 - Bring in da Noise & Heat !

Noise Levels coming from the graphics card

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.

	TYPICAL SOUND LEVELS Jet takeoff (200 feet) 120 dBA   Construction Site 110 dBA Intolerable Shout (5 feet) 100 dBA   Heavy truck (50 feet) 90 dBA Very noisy Urban street 80 dBA   Automobile interior 70 dBA Noisy Normal conversation (3 feet) 60 dBA   Office, classroom 50 dBA Moderate Living room 40 dBA   Bedroom at night 30 dBA Quiet Broadcast studio 20 dBA   Rustling leaves 10 dBA Barely audible

Not too bad, the reference cooler though you can hear yet remains silent. We measure roughly 40 DBa from the (entire) test system. The low noise design definitely works fine. This is at idle though.

When we start to stress and heat up the GPU cores the RPM of the fans will increase. Still not bad but our results end at 44 DBa which is noticeable, but not at all annoying.

POV GeForce 9800 GTX core temperatures

Let's have a look at the temperatures these single slot design coolers produce. As always we measured at a room temperature of 21-22 Degrees C.

In idle mode you'll notice fine cooling performance; expect a temperature of 55 Degrees C when the GPU idles (desktop mode). And during gaming when heat builds up, heavily stressed the GPU core temperature rose towards roughly 72 Degrees C. Not too bad.