I bought "Allcomponents" 2X4GB ddr3 1066MHz memory from newegg. I tried to replace the 2X1GB chips in the 2010 mid macbook. When I inserted the two new chips and turned it on, it kept beeping. And then, I removed one chip and left one in either slot, it still kept beeping. And then, I added one 1GB chip to form a 1+4 GB combination, it worked! And then, I changed the 4GB to the other one, it still worked. And the os X can recognize the 5GB. Strange, right? Do I need to buy any special model designed for macbooks?