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Discussion in 'iMac' started by bigboy99, Nov 13, 2009.
How much ram will my iMac (5,1) running 10.6.2 address? The limit was 3GB with 10.5.
3GB is all the machine supports and is capable of using.
4GB can be installed, and there will be a slight performance benefit, but the machine will still only use 3GB of it.
Its a hardware limitation, not software, because the logicboard has only 32-bit EFI.
Thanks for the clarification. I'm upgrading this week as the 1GB that came with the computer is ridiculous, and I thought it might be an OS issue. The specs indicate "if 4GB is put in, OSX 10.5 will recognize it as 4GB, but will still only address 3GB." I was hoping this might have been fixed in Snow Leopard, but as it's a hardware limitation no sense in buying the extra 1GB.
32 bit supports up to 4 gigs of ram.
2^32= 4,294,967,296 bytes (4.2 gigabytes) for 32 bit.
Most systems either use 3gigs or 2gigs of actual ram though, because ALL of the computer's memory is shared for usage (such as video card memory), up to that 4 gig limit.
Can you ball park the performance increase I might see from adding the last GB (4GB total) even though only 3GB can be addressed at once?
Thanks. 3GB is the best performance value.