Page 4 (Power & Audio)

Le pouvoir "The Power"

We'll now show you some tests we have done on overall power consumption of the PC. Looking at it from a performance versus wattage point of view, the power consumption is really not bad. Our test system is a Core 2 Duo X6800 Extreme Processor, the nForce 680i SLI mainboard, a passive water-cooling solution on the CPU, DVD-ROM and WD Raptor drive. Have a look.

Both cards are at roughly this this number.

The methodology is simple: we look at the peak wattage during a 3DMark05 session with hefty IQ settings to verify power consumption. It's a good load test as both GPU and CPU are utilized really hard here. Please do understand that you are not looking at the power consumption of the graphics card, but the consumption of the entire PC.

We had a total system wattage peak at roughly 230-235 Watts for any 8600 edition card, which is not excessive. We simply place a wattage meter in-between the PSU and power socket. It's not the most objective way to test as you have to consider PSU efficiency as well, but it's the closest thing we can do though.

My recommendations:

• A single GeForce 8600 GT/GTS requires you to have a 350 Watt power supply unit at minimum if you use it in a high-end system. That power supply needs to have (in total) at least 24 Amps available on the 12 volts rails.
• A second GeForce 8600 GT/GTS installed on this system requires you to have a 450 Watt power supply unit at minimum if you use it in a high-end system. That power supply needs to have (in total) at least 30 Amps available on the 12 volts rails.

There are many good PSU's out there, please do have a look at our many PSU reviews as we have loads of recommended PSU's for you to check out in there. What would happen if your PSU can't cope with the load?:

• bad 3D performance
• crashing games
• spontaneous reset or imminent shutdown of the PC
• freezes during gameplay
• PSU overload can cause it to break down

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.

We startup a benchmark and leave it running for a while. The fan rotational speed remains constant. We take the dBA meter, move away 75 CM and then aim the device at the active fan on the graphics card.

We measure roughly 45 dBa on the reference cooled 8600 GTS card, and 46 dBa on the iChill version. So noise wise... there really isn't a difference also.

Despite that overall these are really acceptable sound levels coming from the PC. Again, this is a very subjective test and that dBa level includes all noise in the environment.