i need help upgrading RAm, i went on the OWC website and noticed two different 4gb upgrades for my macbook, one costs 150 the other costs 50 whats the difference? here are the links
http://eshop.macsales.com/item/Other World Computing/5300DDR2S4GB/
http://eshop.macsales.com/item/Other World Computing/53IM2DDR4GBK/
http://eshop.macsales.com/item/Other World Computing/5300DDR2S4GB/
http://eshop.macsales.com/item/Other World Computing/53IM2DDR4GBK/