Testing (continued):
Thermal Testing:
Now that performance testing is done, the next step was to monitor the GPU temperature while the cards were at idle and under a heavy load.
HWMonitor 1.08 was used to monitor GPU temperatures with the cards running on a test platform (no case) in a room with a constant 21C air temperature. The system was allowed to idle at the Windows desktop for at least one hour before the idle temperature was recorded, and then 3DMark06 was executed so that it conducted each test three times before exiting. At this point the maximum temperature reported by HWMonitor was logged.
As you can see from the data provided above, the HD3870 X2 idles at 46C, which is definitely the hottest of the bunch. When the GPUs get taxed heavily the heat does rise fairly high, but the large cooling fan kicks in to keep it from being the hottest card. The noise from the cooler at idle is noticeable, but when it really gets cranking it is much louder. Adding some sort of supplmental cooler isn't necessary, but it might be a good idea to help keep things cool and quiet.
Power Consumption Testing:
Monitoring the power consumed by each video card was the final test executed. This test involved connecting a
Seasonic Power Angel to the power supply in order to monitor the Wattage drawn by the system from the power outlet. The system was allowed to idle at the Windows desktop for several minutes in order for the reading on the Power Angel to stabilize, and then the idle Wattage value was recorded. 3DMark06 was then executed once again and the Power Angel was monitored in order to identify the maximum value achieved.
A twist to my approach is that the initial test was conducted with a 64MB Radeon X300SE installed into the system specified in the configuration section of the review. This extremely low end card draws the least amount of power possible while still letting me see the screen in order to control the system. The point of this was to record a power consumption differential value for the four cards being compared, so we are only looking at the Wattage increase and not total system power consumption. For reference, with the X300SE installed the system drew a total of 69 Watts at idle and 115 Watts under a heavy load.
Checking the values above reveals that using the 1GB
Sapphire HD3870 X2 resulted in a 52 Watt increase in power consumption while idle, and a whopping 209 Watt increase under a load. Under a heavy load the HD3870 X2 requires 111 Watts more than the single HD 3870. This surprised me, and what it indicates is that two HD3870 cards in Crossfire would draw less power than this one HD3870 X2. If you plan to setup up to a graphics card like this, be sure you have a beefy power supply. The specifications recommend a 550W unit as a minimum, and I would suggest getting a high quality unit rated for even more.
