ATI Radeon X1950 Pro vs. GeForce 7900 GS: Noise and Power Consumption

We measured the level of noise produced by the graphics cards’ coolers with a digital sound-level meter Velleman DVM1326 (0.1dB resolution) using A-curve weighing. At the time of our tests the level of ambient noise in our lab was 36dBA and the level of noise at a distance of 1 meter from a working testbed with a passively cooled graphics card inside was 40dBA. We got the following results:

The ATI Radeon X1950 Pro boasts excellent noise characteristics. Its cooler’s fan is rather noisy by itself, but you can only hear it for the first few seconds after you turn your PC on. After that, the level of noise goes down to the measured value, 40.1dBA. This is very low, considering the background noise and the noises from the other components of the working testbed. Subjectively, the graphics card is not heard at all against the background of a working PC. We are not sure if the speed management controller on the Radeon X1950 Pro supports higher speeds because we couldn’t manage to make the card increase its fan speed even when testing it under maximum load.

The Nvidia GeForce 7900 GS behaves in a similar manner. As opposed to the GeForce 7900 GT, this card is equipped with a full-featured speed controller, so there is no problem with high noise level as before. The fan is working at its highest speed for only 1-2 seconds on your turning the PC on. Then it slows down to such a speed that the cooler becomes absolutely quiet. This is confirmed by the results of our measurements. The speed control system is set up in such a way that it has two modes: a quiet 2D and a noisier 3D. But even in the latter mode the GeForce 7900 GS has somewhat better results than the recognized leader in quietness, the GeForce 7900 GTX card.

There’s no sense in comparing the GeForce 7900 GS with the Radeon X1950 Pro because the difference between the noise characteristics of the two graphics cards is so small that it can only be caught by a measuring instrument, not by ear. So, we can say the cards are equally quiet at work.

The power consumption of the ATI Radeon X1950 Pro and the Nvidia GeForce 7900 GS was measured according to our traditional method on the following testbed:

• Intel Pentium 4 560 CPU (3.60GHz, 1MB L2 cache)
• Intel Desktop Board D925XCV
• 2x512MB PC4300 DDR2 SDRAM
• Samsung SpinPoint SP1213C (120GB Serial ATA-150, 8MB cache)
• Microsoft Windows XP Pro SP2 with DirectX 9.0c

The mainboard in this testbed is modified: measuring shunts are connected inline into the power lines of the PCI Express x16 slot. The shunts have connectors for measuring instruments. The 2xMolex → PCI Express power adapter is also equipped with such a shunt. We perform our measurements with a Velleman DVM850BL multimeter that has a measurement accuracy of 0.5%.

To create a 3D load on the graphics card, we ran the first SM3.0/HDR test from Futuremark 3DMark06 in a loop at 1600x1200 resolution with 16x anisotropic filtering. A Peak 2D load was created by launching the 2D Transparent Windows test from Futuremark PCMark05. Here are the results:

The new ATI Radeon X1950 Pro is no record-breaker in terms of power saving. At least its power consumption proved to be higher than we had anticipated. The new card consumes less than the Radeon X1900 GT but only by 9.3W under max load. The integration of the compositing engine is unlikely to have affected that. The problem must be in the rather large number of transistors (more than in the R520) and the higher, in comparison with the opponent, core frequency. Considering these factors, the result is good enough, yet we would want to see more from the 0.08-micron tech process.

The power consumption of the GeForce 7900 GS is a little lower than that of the GeForce 7900 GT, quite in accordance with the disabled processors (four pixel and one vertex). Of course, the card can’t show as superb results as the G73-based solutions do, but it is more economical than the Radeon X1800 GTO and much more so than the Radeon X1900 GT or the X1950 Pro.

The detailed picture has nothing new to tell us. As expected, the GeForce 7900 GS behaves like its elder brother, having a near zero consumption on the +3.3V line. In 3D mode, however, the external +12V line bears a somewhat higher load than the internal one, but the difference is less than 5 watts.

The Radeon X1950 Pro behaves differently. Like all modern graphics solutions from ATI Technologies, it loads the +3.3V line heavily. It also puts a higher load on the internal +12V line in 3D mode than on the external one.

So, our tests show that the GeForce 7900 GS is a more economical solution than the Radeon X1950 Pro, but the G71 GPU, although manufactured on a “thicker” tech process, is less complex and works at a lower clock rate than the ATI RV570. It is thanks to this moderate appetite that the GeForce 7900 GS can do without a massive cooling system and is quite satisfied with the compact reference cooler from Nvidia without any danger of overheat whereas the Radeon X1950 Pro has to use a rather massive cooler with well-developed ribbing.

ATI Radeon X1950 Pro vs. GeForce 7900 GS: Overclocking

Unfortunately, we couldn’t check out the overclocking potential of the Radeon X1950 Pro because there were no overclocking utilities that would support the RV570 chip at the time of our writing this review. ATI’s Overdrive feature in the Catalyst Control Center worked incorrectly, at least with our sample of the Radeon X1950 Pro. When we tried to increase the GPU clock rate, the frequency was stepped up so high that we got visual artifacts right away. We will try to overclock the Radeon X1950 Pro in the future as soon as we’ve got a retail version of the card and appropriate utilities.

The GeForce 7900 GS met our expectations in the overclockability tests. The reason of its success is obvious – a solid reserve of core frequency because the same G71 chip works at 650MHz on the GeForce 7900 GTX. We only set an additional 120mm fan to blow at the card’s PCB and achieved stability at 580/850 (1700) MHz frequencies. This amounts to a 30% core frequency growth and a 20% memory frequency growth. Our overclocked GeForce 7900 GS surpassed the GeForce 7900 GTX in terms of memory frequency and equals the GeForce 7800 GTX 512 whose memory was clocked at the highest frequency among all of Nvidia’s cards, 850 (1700) MHz.

As for the graphics core frequency, we didn’t modify the frequency delta of our G71 chip, so the pixel and vertex processors and the TMUs worked at 580MHz and the ROPs were clocked at 600MHz. This good overclocking achievement provides an appropriate performance growth as you will see right now in the gaming tests.