Hi, Just upgraded my Macbook Pro 13" mid-2009 with a Crucial MX100 128 GB. It's definitely runs faster now, however, now the battery last for a significant shorter time. I am running yosemite. The list below is everything I have tried so far: 1. Reset SMC/PRAM/NVRAM 2. Checked (using activity monitor) if there was an application hogging the power. There wasn't. 3. Switched out the SSD with the old HDD. The was no battery drain problem with the HDD. 4. Checked if there were any driverupdates. There wasn't. 5. Lastly I tested the SSD in another Macbook Pro 13" mid-2009 running Mavericks. In this case there was no noticeable batterydrain, but no increased batterylife either. (Shouldn't the SSD increase batterylife??) So for me it seems that yosemite could be the problem when I use the SSD. I really don't know what else to try. Really hope there is someone out there who could help!