Right, at this stage we are going to insert and connect the graphics card into our test setup. Installing the card into your system will be a fairly easy job. Just slide the card into a free PCIe x8/x16 slot, connect the DVI cable to one of the DVI connectors, connect both the 6-pin power connectors to the card.

Especially with a card like this... I do recommend you buy a decent PSU with some reserves, always. The PSU is an extremely important component in your PC. We'll get into that in a minute though.

Once the card is installed we startup Windows. We install our driver, reboot and you should be good to go. The card will work straight out of the box.

Power Consumption

So then, first off, he 55nm GeForce GTX 175 (55nm) has a ~219W TDP.

We'll 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 not as bad as I expected it to be. Looking at it from a performance versus wattage point of view, the power consumption is really good with the new 55nm products.

Sidenote: We recently upgraded our test-platform, which by itself utilizes a lot of energy.

The new test PC is based on Core i7 965 / X58 based and overclocked to 3.75 GHz. Next to that we have energy saving functions disabled for this motherboard and processor (to ensure consistent benchmark results).

The ASUS motherboard also allows adding power phases for stability, which we enabled as well. I'd say in total on average we are using roughly 50 to 100 Watts more than a standard PC due to these high-end settings and then add to that the CPU overclock, water-cooling, UV lights, optical drive and HDDs. Keep that in mind.

Our normal system power consumption is higher than the average system.

• System in IDLE = 228 Watts
• System with GPU in FULL Stress = 420 Watts

So here's my power supply recommendation:

GeForce GTX 275

• A GeForce GTX 275 requires you to have a 550~600 Watt power supply unit at minimum if you use it in a high-end system. That power supply needs to have (in total accumulated) at least 40 Amps available in total on the 12 volts rails.

GeForce GTX 275 SLI

• A second GeForce GTX 275 requires you to have a 800 Watt power supply unit at minimum if you use it in a high-end system. That power supply needs to have (in total accumulated) at least 50+ 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

GPU temperatures

So pretty much once we fire off a hefty shader application at the GPU and start monitoring temperature behavior as it would be mid-gaming, we literally stress the GPU 100% with our test. We measured at a room temperature of 21 degrees Celsius.

I'll add some other GTX 275 cards we recently tested.

On average at idle you can expect a temperature of 40~45 degrees C / 111 F. Pretty normal. Once we push the GPU to 100%, the temperatures take a pretty hefty toll and jump over 80+ Degrees C ~ 179 F. This remains fine within designed operational specifications, but it's quite hot alright.

The eVGA card is a post launch production card and as it seems a little better with it's temperatures. Of course the other cards, besides the reference, are all pre-overclocked and as such can run a little warmer.

Here you can see how we measure -- this is the eVGA GTX 275 card by the way.

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 test the cards on dBA levels. Obviously the reference coolers all perform roughly the same. The customized coolers are either louder or softer depending on what they try to achieve.

The noise levels are based in a stressed environment, meaning the GPU was (overloaded) with a heavy shader application (FurMark).

• eVGA GeForce GTX 275 idle: 38 DBa
• eVGA GeForce GTX 275 idle: 41 DBa

The card has a reference cooler, and that one works pretty well really. In idle, desktop mode you will not be able to hear the cooler at all. Once the GPU starts to heat up you'll hear it softly.

So to sum it up, the reference cooled models are relatively quiet graphics cards, we like that very much.