I've noticed that when I went from 4 to 8 GB (standard factory 4GB RAM to 8GB Crucial) on my 13 inch MBP (5,5 C2D, late 2009, SSD) that it 'hangs' and that when I am typing fast that the text appears much slower than when I type it. This happens more once the system has been put into and out of sleep numerous times without restart. Even internet browsing has a slight delay after a few days without a restart. Any idea why this is? Performance wise, benchmarks show no real difference between 4GB and 8GB, so I don't understand why it would develop a delay that it has never had before Furthermore, are there any software actions that should be done when upgrading RAM (system resets or any action different than physically installing the RAM into the computer)?????