Noise and Power Consumption
We measured the level of noise produced by the ATI Radeon X1950 XTX’s cooler 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 new cooler from ATI is almost noiseless and is only 0.8dBA louder than the passive solution most of the time. It’s only after long working in 3D mode that the fan begins to work at a higher speed, and the level of noise grows to 47.1dBA, which is still somewhat quieter than the GeForce 7950 GX2. At a distance of 5 centimeter the soft rumble of the fan bearing is the main source of noise.
The cooler is indeed silent subjectively and only reminds of itself when the GPU temperature reaches a certain threshold value. The spectrum of its noise is different from the Radeon X1900 XTX’s cooler and without that characteristic “plastic” tone. The noise seems quieter and softer despite the reading of the sound-level meter. So, ATI had succeeded in developing a very quiet and efficient cooler. There’s no need to replace it unless you plan to equip your gaming platform with a liquid or cryogen cooling system.
Then we measured the power consumption of the new graphics card on the following testbed:
- Intel Pentium 4 560 CPU (3.60GHz, 1MB L2 cache)
- Intel Desktop Board D925XCV
- PC4300 DDR2 SDRAM (2 x 512MB)
- Samsung SpinPoint SP1213C hard disk drive (120GB, Serial ATA-150, 8MB cache)
- Microsoft Windows XP Pro SP2, DirectX 9.0c
The mainboard in this testbed was specially modified: we connected measurement shunts into the power lines of the PCI Express x16 slot and equipped them with connectors to attach measuring instruments. We also added such a shunt to a 2xMolex → PCI Express adapter. The measurements were performed with a Velleman DVM850BL multimeter (0.5% accuracy).
We loaded the GPU by launching the first SM3.0/HDR graphics test from 3DMark06 and running it in a loop at 1600x1200 resolution and with enabled 16x anisotropic filtering. The Peak 2D load was created by means of the 2D Transparent Windows test from Futuremark’s PCMark05 benchmarking suite. The results follow below:
The power consumption of the new Radeon X1950 XTX is nearly that of its predecessor, being only 4W higher under Max 3D load and 3.5W higher in Peak 2D mode. But the use of GDDR4 and the changes in the power circuit design have led to a different distribution of load across the lines:
It has become somewhat more balanced, although it is still the external +12V line that is under the highest load in 3D mode. Note also the increased load on the +3.3V line which used to supply 5.5W previously, but now supplies 6.5W.
Unfortunately, we can’t directly compare the Radeon X1950 XTX and the GeForce 7950 GX2 in this test because the latter refuses to work on the mainboard installed in our testbed. These cards should have comparable power consumption, though. By our estimate, the dual-chip solution from Nvidia consumes about 110-120W. Not yet having any accurate data about the power consumption of the GeForce 7950 GX2 we have to name the Radeon X1950 XTX the most voracious premium-class graphics card of today. Anyway, one such card can be easily fed by any high-quality 450W ATX 2.0 power supply. For building Radeon X1950-based CrossFire systems ATI recommends using a 550W or higher power supply. This rather moderate requirement is partially due to the low consumption of the CrossFire Xpress 3200 chipset.