3 - Power Consumption, Heat and Volume levels
It's time to do some actual testing. We'll start off by showing 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 good with the new 55nm products. Our single card test system is a Core 2 Duo X6800 Extreme Processor, the nForce 680i SLI mainboard, a passive watercooling solution on the CPU, 2GB memory, DVD-ROM and WD Raptor drive. Have a look:
System Under load
|GeForce 9800 GTX+||302 Watt|
Performance is on par with any modern mid-range graphics card. Our system IDLE power consumption was roughly 170 Watts, by the way.
In my view the card series requires you to have a 500 Watt power supply unit at minimum if you use it in a high-end system, and I think that's barely on the safe side. Also recommended is 32 AMP's on the 12 volts rails for stable power distribution (on a single card configuration). Notice that the card uses two 6-pin power connectors.
There are many good PSU's available, over the years we reviewed a lot of them and have loads of recommended PSU's for you to check out in there, have a look. Things that can 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
The thermal envelope
Let's have a look at the temperatures these cards produce. We measured at a room temperature of 21-22 Degrees C, look at the idle temperature and then load the GPU 100% for a couple of minutes and measure the temperature once a second and follow the temperature delta.
The GTX+ as a dual slot product will show pretty decent temperatures due to the nature of the cooler. Temperatures: idle 55-60 degrees C with a ~75 degrees C load temperature.
Obviously, always make sure you have a very well ventilated PC.
Noise Levels coming from the graphics card
When graphics cards produce a lot of heat, that heat usually 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|
We start up 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.
Though audible when it spins up (as the GPU will get hotter), it's noise levels are not bad. Expect roughly 43 DBa when the GPU is fully stressed.