Fri Aug 17, 2012 4:30 pm
The PI's polyfuse (F3) will limit it's ability to use anything more than 750ma so even if you use a power supply rated at 5v@2A or 5v@750ma the extra current won't make a difference.
What does matter is the effectiveness of a power supply to keep a steady voltage with respect to current most loaded power supplies will drastically drop their voltage output.
The only way to test this on the PI is to load the board with USB device and then measure the voltage at TP1 / TP2 the PI really needs 4.75v or higher to function correctly.
Richard S.