I upgraded the ram of my 17 " 2.66 GHz core 2 duo Macbook pro from 4gb to 8gb, but when i look at the activity monitor the computer shows only 7,75gb. On the menu "about this mac" it shows 8gb. Is it normal? I also had some problems extracting the lower stick, once it popped up it wouldn't come out and I had to force it out. Could this be the reason?
It is normal.
Intel HD Graphics
Intel HD Graphics allocates a base amount of 256 MB for video and boot processes at startup. For example, a MacBook Pro (15-inch, Mid 2010) with 4 GB of RAM installed has 3.8 GB of memory available to Mac OS X and applications (4096-256=3840).