At 4.5 pounds, the Timeline M3 is very light for a 15-inch laptop, and even with the 65W power brick factored in, it weighs only a scant 5.25 pounds. Acer dubs this machine an Ultrabook, which just goes to show how vague that moniker is. Still the M3 is sleek and quite light for so large a laptop.

It's no slouch in the performance department, either. The combination of a Core i7-2637M low-voltage processor, graphics, and a 256GB yields an impressive WorldBench 7 score of 155--one of the highest performance scores we've seen for a machine in the category. The M3 also lasted for more than 8 hours in PCWorld's battery life test.

So what's not to like?

The LCD--the most visible component in the system--is a 15.6-inch panel that delivers a puny resolution of 1366 by 768 pixels. That might work for a 13.3-inch Ultrabook; but at the M3's larger screen size, you'll notice the "screen door" effect of individual pixels while watching video content. On top of that, the range of satisfactory viewing angles is quite narrow. If you watch content from outside that range, you'll see substantial color and contrast shifting. This system cries out for a true 1080p, IPS LCD panel.

The system incorporates Nvidia's power-saving system, which allows the Intel HD 3000 integrated graphics to run during normal use, but fires up the Kepler-based GT 640M GPU when the demands of 3D gaming render the Intel graphics inadequate. You can specify which GPU to use in key applications, so we tested both Nvidia and Intel graphics when playing back DVD and HD video. In those tests we noticed distracting levels of mosquito noise while playing our The Return of the King DVD with Intel graphics. The noise disappeared when we switched to using the Nvidia GPU, but the overall image suddenly looked washed out and excessively bright. HD content fared slightly better, but visible noise persisted in our Magic of Flight test clip.