I have a MacBook Pro and older 505, and I haven't had any problems. However, I find that charging with the Mac takes 3X longer than charging with the Windows machine. I only presume the 950 needs more power because it has a bigger battery and screen. The bottom line is you need to not charge via USB. You need to buy this
http://www.amazon.com/Charger-WALL-p...dp/B001CEA2YC/
OK, it doesn't have to be this one, this was just the first one I could Google. It is a cable (I happen to like the retractable feature) that has USB on one end and Sony PSP on the other end. This charges your reader through the round power port and doesn't fool with the linking to your computer. This only takes power from the computer, and it puts it directly into the battery. No goofy protocols needed. Plus you get a wall wart and car wart to make USB without using your expensive computer as a not-very-good power supply.