ATI HD3850 & HD3870: Improved Acoustics & Power Efficiency

TEST METHODOLOGY

Our test procedure is an in-system test, designed to:

1. Determine whether the card's cooler is adequate for use in a low-noise system. By adequately cooled, we mean cooled well enough that no misbehavior related to thermal overload is exhibited. Thermal misbehavior in a graphics card can show up in a variety of ways, including:

• Sudden system shutdown or reboot without warning.
• Jaggies and other visual artifacts on the screen.
• Motion slowing and/or screen freezing.

Any of these misbehaviors are annoying at best and dangerous at worst — dangerous to the health and lifespan of the graphics card, and sometimes to the system OS.

2. Estimate the card's power consumption. This is a good indicator of how efficient the card is and will have an effect on how hot the stock cooler becomes due to power lost in the form of heat. The lower the better.

3. Determine the card's ability to play back high definition video, to see if whether it is a suitable choice for a home theater PC.

Test Platform

• Intel Pentium D 930 Presler core processor. Official TDP of 95W.
• AOpen i945Ga-PHS motherboard - Intel i945Ga Chipset; built-in VGA.
• Gigabyte G-Power 2 Pro heatsink, modified with a Scythe Slip Stream 500RPM 120mm fan.
• Corsair DDR2 RAM, PC2-6400, 1024 MB
• Seagate Momentus 5400.3 160 GB, 5400RPM, ATA/100, 2-platter notebook hard drive, suspended
• Seasonic S12-600 ATX12V v2.0 compliant power supply, modified with a Scythe Slip Stream 800RPM 120mm fan @ 5V.
• Antec P180B case, modified in detail below.
• Nexus 120mm fan connected to a variable fan speed controller.
• Microsoft Windows XP Professional operating system
• ATI Catalyst 8.2 graphics driver
• QuickTime Alternative 1.81 codec package

Measurement and Analysis Tools

• ATITool version 0.26 as a tool for stressing the GPU and to show GPU temperature
• CPUBurn P6 to stress the CPU
• SpeedFan version 4.33 to show CPU temperature
• Cyberlink PowerDVD 7 to play video.
• Seasonic Power Angel AC power meter, used to measure the power consumption of the system
• A custom-built variable fan speed controller to power the system fan
• Bruel & Kjaer (B&K) model 2203 Sound Level Meter. Used to accurately measure SPL (sound pressure level) down to 20 dBA and below.

The anatomy of our test platform is detailed here: Updated VGA Card/Cooler Test Platform

Testing Procedures

Our first test consists involves recording the system power consumption using a Seasonic Power Angel as well as CPU and GPU temperatures using SpeedFan and ATITool (or just SpeedFan if a nVidia based card is used) during different states: Idle, with CPUBurn running to stress the processor, and with CPUBurn and ATITool's artifact scanner running at the to stress both the CPU and GPU simultaneously. This last state mimics the stress on the CPU and GPU produced by a modern video game. The software is left running until the GPU temperature stabilizes for at least 10 minutes. If artifacts are detected in ATITool or other instability is noted, the heatsink is deemed inadequate to cool the video card in our test system.

If the heatsink has a fan, the load state tests are repeated at various fan speeds while the system fan is left at its lowest setting of 7V. If the card utilizes a passive cooler, the system fan is varied instead to study the effect of system airflow on the heatsink's performance. A B&K Sound Meter is employed to take system noise measurements at each fan speed.

Video Playback Testing

For our second test, we play a variety of H.264 and VC-1 video clips with PowerDVD. A CPU usage graph is created via the Windows Task Manger for analysis to determine the approximate mean and peak CPU usage. If the card (in conjunction with the processor) is unable to properly decompress the clip, the video will skip or freeze, often with instances of extremely high CPU usage as the system struggles to play it back. High CPU usage is undesirable as it increases power consumption, and leaves fewer resources for background tasks and other applications that happen to be running during playback. Power draw is also recorded during playback.

Video Test Suite

1920x816 | 24fps | ~10mbps

H.264: Rush Hour 3 Trailer 1 is encoded with H.264. It has a good mixture of light and dark scenes, interspersed with fast-motion action and cutaways.

1440x1080 | 24fps | ~8mbps

WMV3: Coral Reef Adventure trailer is encoded in VC-1 using the WMV3 codec (commonly recognized by the moniker, "HD WMV"). It features multiple outdoor landscape and dark underwater scenes.

1280x720 | 60fps | ~12mbps

WVC1: Microsoft Flight Simulator X trailer is encoded in VC-1. It's a compilation of in-game action from a third person point of view. While the source image quality is poor compared to the other videos in our test suite, it is encoded using the Windows Media Video 9 Advanced Profile (aka WVC1) codec — a much more demanding implementation of VC-1.

Estimating DC Power

The following power efficiency figures were obtained for the Seasonic S12-600 used in our test system:

Seasonic S12-500 / 600 TEST RESULTS
DC Output (W)	65.3	89.7	148.7	198.5	249.5	300.2
AC Input (W)	87.0	115.0	183.1	242.1	305.0	370.2
Efficiency	75.1%	78.0%	81.2%	82.0%	81.8%	81.1%

This data is enough to give us a very good estimate of DC demand in our test system. We extrapolate the DC power output from the measured AC power input based on this data. We won't go through the math; it's easy enough to figure out for yourself if you really want to.