Did this 8 GB memory ordered to expand the 4 GB that were in my Macbook. I had ordered a different memory before this purchase, but my laptop did not start with this and made a scary hooting instead of boot. The RAM of CSX I had absolutely no problems, installation was done in 2 minutes (using a screwdriver) and the Macbook started normally. The 8GB you could tell very, for example when starting the program or other operations that require more RAM. The laptop can be brought much less from the rest of the memory and brings a real appreciation, as everything goes a little faster than usual. To start Word, Excel or iTunes within a few seconds while this has previously taken me much longer. I can wholeheartedly recommend the product so but everyone should check in advance whether the memory is exactly the right one for his laptop. On my Macbook Pro mid 2010 this was the case and therefore from me 5 stars.