I've had my TC4400 for like a month now and I'm pretty please with it. Through this month of usage, I noticed something weird. While the laptop is running on pure battery, randomly... the screen would flicker. (Like... change from the highest brightness to a lower brightness and back to its orginal brightness.) This process occurs in a matter of less than a second.. so sometimes it is hard to notice it. Conditions for this thing to happen: 1) Laptop is running only on the 6 cell battery 2) Ambient sensor is disabled 3) Screen is turned up to the brightest Problem DOES NOT OCCUR when: 1) Laptop is plugged in I've noticed this problem on my older Dell CPi when the battery was like at 4% critical condition. However, this flickering (which occurs only about 10-15 times RANDOMLY in the 3-4 hour battery discharge) is independent of the amount of battery that is left in the laptop. (e.g. it occurs at 99% and at 6%) For people who have TC4400... try running your laptop just on its battery and ... work on it for the complete time (3-4 hours) of discharge. Do you see any of these symptoms? Do you think it's a battery problem or a screen problem?