Geforce GTX 275 & Radeon HD 4890: Power consumption, Loudness and Cooling
Our test system for loudness, power consumption and temperature (pictured with a GTX 295) [Source: view picture gallery]
To check how loud the graphics cards are, we use a silent test system consisting of a AMD Athlon X2 BE-2350 at 2.1 GHz on a Asrock A780 FDP with an AMD 780G chipset, a Forton Zen PSU with 400 watt and a SSD from Hama. The CPU is passively cooled by a Scythe Orochi. AT a distance of 50 centimeters we record the loudness in Sone and the acoustic pressure in Decibel (a).
Besides the 2D loudness and temperature we also record workload results. For this we use Race Driver Grid at 1,920 x 1,200 with 4x MSAA and 16:1 AF. The game is more challenging to the graphics card than Crysis Warhead and many other games and delivers a continuous workload. As an absolute worst-case scenario we use Ozone3D Furmark version 1.6.5 that is an real stress test for the cooling system and the chips themselves. Attention:
This is a worst-case scenario that reveals the absolute maximal loudness and temperature possible - but Furmark actually is anything else than an everyday workload. Cooling solutions of the HD 4890 and GTX 275
The cooler and the fan of the Geforce GTX 275 match those of the 55 nm GTX 260. Compared to the 65 nm version this solution has one heatpipe less, the aluminum fins are a little shorter and the copper plate is slightly smaller. AMD on the other hand overhauled the cooling solution of the HD 4890: Three instead of two heatpipes transfer the heat from the copper base to the aluminum fins and the fan has a little more space. The red plate that cools the voltage converters and the VRAM has got a little more surface. Results: Radeon HD 4890
Radeon HD 4890: The memory frequency is not lowered in 2D mode [Source: view picture gallery]
In idle mode the HD 4890 reaches 2.4 Sone. The power consumption is 60 watt (HD 4870/1G: 55 watt) and taking a look at the idle clock speeds reveals the reason: Even in idle mode the GDDR5 video memory is running at its full 975 MHz in stead of being set to a lower frequency. You can only lower the clock speed manually with certain tools - at your own risk of course. The graphics chip on the other hand is running at 240 megahertz only if in 2D mode. As fan speed is regarded our three samples deliver different results when stressed with Furmark: they vary between 2,600 and 3,300 rpm.
In Race Driver Grid we received the following results:
• Loudness: 6.3 Sone (~2,300 rpm)
• Temperature: 84 degrees Celsius
• Power consumption (graphics card only): ~158 watt
• Compare: HD 4870/1G: 139 watt; HD 4850: 91 watt; HD 4870 X2: 255 watt
• 8.2 to 10.2 Sone
• 226 watt (HD 4870/1G: 200 watt; HD 4850: 150 watt; HD 4870 X2: 364 watt) Results: Geforce GTX 275
Geforce GTX 275: The card is clocked down in idle mode [Source: view picture gallery]
In idle the GTX 275 reaches quiet 1.2 Sone. Due to the working 2D mode with noticeably lowered frequencies the power consumption is 34 watt. Although this result is comparatively low, it is just the level of the GTX 280 and not the one of the GTX 285 (27 watt).
In Race Driver Grid we received the following results
• Loudness: 3.6 Sone
• Temperature: 79 degrees Celsius
• Power consumption (graphics card only): ~163 watt
• Compare: GTX 285: 153 watt; GTX 260 65nm: 148 watt; GTX 260 55nm: 121 watt
• 4.5 Sone
• 215 watt (GTX 285: 208 watt; GTX 260 55nm: 159 watt)
The power consumption results are rather irritating given the results of the 55 nm cards. Rumors say that Nvidia used "old” GT200 GPUs (GTX 280/260 65 nm) for the new boards. But removing the cooler reveals a GT200b with a B3 stepping.