Originally Posted by gdog
i just put in 4 gigs of memory in a 2007 imac 24 inch 2.33 core 2. this mac is only supposed to accept 3 gigs total. i don't know if this is because of snow leopard but i think so. shows up as 4 gigs in about this mac.
32-bit OSes and computers can utilize up to 4 GB of RAM. The OS reserves 1 GB of address space for shared memory devices such as video. Thus leaving only 3 GB address space remaining to use for applications.
Leopard (and Windows XP) "displayed" that only 3 GB RAM was available, which is true, but misleading. MS changed the display in Vista to show it can see the full 4 GB. Snow Leopard also changed the display. Thus, it seems like Snow Leopard increased the memory it can use, but this is just a display change.
I have a mid-2007, 24 inch, 2.4Gh iMac, and an older MacBook. I've tested this on both and can see clear performance increases as I change from 2 GB to 3 GB to 4 GB Ram. The same performance increases are noticable when I use my bootcamp Win XP as well.
[Before anyone jumps on me - I personally choose to use Apple, but I get paid to teach Windows and Linux classes at the college. "... the school pays me to use Windows." ]