Both peices of ram are DDR2. My Kingston Ram only runs at higher speeds in my other desktop. The top one in my sig (but the ram was suited for that machine in the first place) and when I put the ram in my other desktop(the hackintosh rig in my sig) it only runs at half the speed it runs in my other desktop.
The ram that is compatible with your hacintosh is PC-4200,that is the max speed of ram your computer will operate at. that is 533mhz in ddr2, meaning 266 clock speed. If you put ram in with higher speed than this it will default to this speed, as it doesn't support faster speeds.
If the ram is from the other computer is PC-8500 that is 1066mhz ram, with a clock speed of 533mhz. and what you are seeing is correct.
As for the amount of ram you are seeing:
Your computer has many methods in which to use memory. There is memory storage and caches all over the motherboard. These devices contain some of the below method of storage:
- Dynamic Ram
- Static Ram
- Flask Memory
- Virtual Memory
- Video Memory
For example, your sound, video, keyboard, chipset caches, I/O controller (IDE, SATA, etc) caches . . . These devices with discrete and cache RAM need to have their "Addresses" so that the computer knows where they are in order to query and access them.
You computer also has System Resource Memory. This an index of addresses that tell the computer where everything is for access as mentioned earlier. The computer needs to know that a certain boundary of addresses will contain certain functions to perform when commanded.
Memory-mapped devices (such as your video card) will use some of that physical address space, as will the BIOS ROMs. After all the non-memory devices have had their say, there will be less than 4GB of address space available for RAM below the 4GB physical address boundary. Now a 32bit Operating system such as Windows XP 32bit and VISTA 32bit have the ability to access 2^32 bits = 4GB. Now if you have an 8800GTX with 768MB of DRAM, then that memory must be addressed in the space of the 4GB and you lose some of the system dram to the addressing. This continues with all other devices, leaving you with less than the 4GB. Since Windows can address up to 4GB, then with 3GB, there will be the 3 --> 4GB mapping so you should not lose that DRAM with 3GB unless your devices demand it. For example, SLi with 2 X 8800GTX 768MB will certainly take away from the 3GB.
If you had a 2 GB system, then the addressing is done in the discrete video card DRAM.
I hope this info helps...