We have all heard the praise of NVIDIA’s new 9400M GPU in Apple’s portable line up. However, they may be more impressive then we were originally led to believe.

Recent test are showing decreased CPU usage when playing back high-definition movie files on Apple’s New GeForce 9400M equipped MacBook Air. Both the old MacBook Air and the new one use a 1.6 GHz Intel Core 2 Duo CPU. There is a difference in bus speed, 800MHz vs 1066Mhz. However it is unlikely that this would affect CPU usage stats on video playback.

When playing back the exact same H.264 HD video file, CPU rates dropped from 87.5% on the old MBA to 42.9% on the new one. More importantly is the fact that when monitoring the actual clock rate, the old MBA maintained a steady 1.4GHz speed whereas the newer model is able to down-clock itself to 0.8GHz. That is almost a 50% drop in CPU usage! This evidence strongly supports the theory that these new chips have some sort of hardware decoding functionality built into them.

These test have yet to be run on other 9400M equipped Macs but I’m guessing you will find similar results.

Via macX.cn