If you are using a 2009 or 2010 Mac Pro, another option is to source out the ram from PC shops. Just make sure the store knows or gets the correct specs of the ram. There are some PC stores that now carry Mac computers like PC Gilmore, Silicon Valley or Complink. They may have tech people to help you. As far as I know it's cheaper to buy at PC stores and the warranty period is longer. Apple Singapore only offers 3 months warranty on ram.