I just upgraded my late 2009 iMac 24" to 8 GB RAM. the RAM is from Strontium and system profiler says that I have 8 GB. but when i open Activity Monitor i get only 7.75 GB. Reading some posts it sugests that the extra 256MB could be the video ram. but when i had 4 GB (the original) activity monitor would show 4 GB. is the RAM bad or is the video card now taking 256 as there is just more ram ?