2. Bread And Circuses: Test Scenarios And Benchmarks

For these tests, we made some changes to our typical notebook testing scenarios. Whereas MobileMark 2005, 3D Mark 2005 and PCMark 2005 gave us a basis for measuring system performance under everyday usage, we decided to limit the battery life measurements we took from MobileMark 2005 to only two scenarios - namely, Office Productivity and DVD Playback.

To get some sense about how long the notebooks could keep going purely on battery power, we constructed an infinite loop around the four games included in 3DMark 2005 at each unit's native display resolution. Basically, we kept looping through all four game demos in sequence until the batteries ran out. This is also a good time for us to observe that several vendors elect to set energy saving options when their notebooks are running on battery, so that the graphics card drivers automatically set memory and CPU clock rates to minimal values. While this might indeed keep a notebook running longer on battery power, it also drives graphics performance right down into the cellar. Fluid, flicker-free gaming wasn't possible on any of these test systems whenever the "Max battery" power scheme (or its vendor-specific equivalent) was in effect.

Acer sets CPU and memory clock rates to minimal values by default when running off the battery

Alienware maintains high 3D performance settings even when the unit runs from its battery

Those who want to maintain the highest possible frame rates when running their notebooks on battery should look carefully at their energy- or power-management schemes. When it comes to graphics card drivers, this means digging either into ATI's PowerPlay utility, or Nvidia's Powermizer software.

Our second round of benchmarks assembled four games from different genres, and included Tomb Raider Legends, Elder Scrolls 4 Oblivion, Spellforce 2, and Need for Speed Most Wanted. These games impose very different demands on the graphics subsystems and displays on the systems on which they're played. The prettiest and most processor-intensive shader effects are visible in Oblivion. In rendering the game's Outdoor level, even the most powerful desktop graphics cards (ATI X1900XTX and NVidia 7800 GTX) bog down. The maximum setting for grass and trees with full details and shadows imposes the greatest drags on 3D performance. The racing game Need for Speed demands not only a fast graphics processor but also very short pixel refresh (or screen redraw) intervals in the display. Otherwise, the background scenery becomes blurry and the game unplayable.