Power, Temperature, And Noise Benchmarks
Of course, there’s more to a graphics card than raw performance. Let’s have a look at other aspects of these products, starting with power draw.
What we’ve done is measure total system power at the wall with a single GeForce 8400 GS installed at idle and we've used the 210 W result as a baseline. We then measured idle power and load power with these cards using only a graphics-intensive load, specifically the Sanctuary demo from Unigine. This engine places extremely taxing demands on the graphics system.
It’s interesting how the Asus 4850 Matrix draws the least power at stock clocks and the most power when overclocked. This is due to the large voltage increase afforded by Asus’ iTracker software when set to higher speeds. Note that the modded Asus card still has a very low power draw at idle, thanks to the 2D setting of the iTracker profile, allowing us to draw even less power with the stock settings when 2D clocks are set low despite the high 3D overclock.
Contrast these results with the Gigabyte GV-N250ZL-1GI, which draws more power than the Asus EAH4850 Matrix at stock speeds, but draws less when both are overclocked. Remember, there is no voltage adjustment on the Gigabyte card, ensuring that even when overclocked there will not be the colossal power increase we see with the Asus product.
With this in mind, let’s have a look at the GPU temperatures:
Here we see results reminiscent of the power draw, but for different reasons. Notice how the Asus Radeon 4850 Matrix is much hotter than the Gigabyte GeForce GTS 250, as the Radeon HD 4850 is known to be a hot-running GPU. Although Asus’ impressive heatpipe cooler keeps it in check, things still get hot when the card is overclocked and voltage is added.
Conversely, we see that the Gigabyte card barely registers a temperature change when overclocked under load compared to the stock clocks. Idle temperature is much higher on the overclocked Gigabyte card.
Finally, let’s have a look at noise. Unfortunately, our test system is rather loud in this case and these cards are so quiet that it was difficult to get meaningful data. In the future we’re going to use a different noise-testing methodology, but for now let’s consider what we have.
The Asus EAH4850 MT has a passive mode, so it’s completely silent at idle. The 55 decibels you’re seeing there is the ambient noise from the system as we had to test the sound close to the cards to get any reading at all. Under normal operation the card is extremely quiet, but as you can see under the extreme overclock and increased voltage mode, we set the fan speed high to keep the temperatures down.
The Gigabyte GV-N250ZL-1GI, on the other hand, remained acceptably quiet across the board. It did produce a little more noise in 2D windows applications since it doesn't have a passive mode, but it’s still a very quiet card.
