Hi I got a macbook pro early 2008 model. My battery has failed and I read on apples website that this causes the cpu performance to run at 50 % max. I bought a new non-genuine battery from ebay (the battery life doesn't matter for me, because it's always plugged in). It worked fine and I could see a huge CPU improvement (ie. game didn't lag). Before on death battery there was always huge lagg when playing games. But recently even on battery the games begin to lag again and the whole laptop has become slower. The battery still does work, because it works fine when the power plug is off. But why does the cpu not run on full power when gaming? as it did for the first day of use. Can I manually force the CPU to run at higher speed? My reason to buy an ebay battery instead of apple, is because it's expensive, very bad (personal experience and forums) and only got 1,5 review stars in over 200 reviews on apple stores' website.