Aporte original por: Jon Fukumoto ,
You should always use the correct type and speed of memory specified by Apple. Always use DDR3 rated at 1066 MHz. On MacBooks (mid 2010), the bus speed is 1066 MHz. Using 1333 won't work, as you found. It's not supported by the motherboard. To be safe and to prevent problems, ALWAYS use the memory specified by Apple. It will save you the headaches down the road.