My stock battery was really becoming a nuisance. It wasn't even lasting two hours. Additionally, there are supposed to be 2 points of percent battery charge to give you fair time to be alerted and plug into power. First you're supposed to get a Low-Battery Alarm at 10% followed by a Critical-Battery Alarm at 3%. At the Low-Battery Alarm, I have a wav file which gives me a clear indication I need to head to a power outlet. One would think I could get up out of my chair, walk into the next room and plug in. Wrong! My old battery went into total nosedive mode and I hit the two warnings Bang-Bang and laptop was dead. Now this new battery provides over 3 hours worth of power. Tonight I've been using my laptop for 1.5 hours and the battery icon says I still have 68% or 2:15 hours left. Wow!! I really hope this battery maintains this trend! It gets my vote!!!