Chosen Solution
Hello, I have a macbook pro 15" mid 2009 and i’ve replaced my logic board. Before the upgrade i have a logic board with a core 2 duo 2.53 GHZ (4gb RAM and no dedicated graphic card). After the upgrade i have a logic board with a Core 2 Duo 2.66GHZ (4gb ram and a 9600M GT graphic card). I haven’t replaced anything else. I have the same HDD with the same OS X install as i have before. But now my macbook pro is too slow some times. For example after opening a folder, the preview of the images is too slow. And crash many times. I have to do a clean install to my macbook pro for everything works fine? PS: I also see that my memory ram is almost close to the max value (4 GB). MacBook Pro, OS X Yosemite (10.10.1)
Try replacing the hard drive cable and possibly the hard drive. I use the newer cables from the 20012 because of the wider path. This cable gets damaged as it makes several 90 degree bends. When replacing I install pads so the bottom cover won’t touch the cable. See this question on the cable to use: Using new hard drive cable in older machines 821-1480-A The machine will also take 8 GB of RAM.
