why the 2gb ram limit on laptops?

[dotman]

why are high end laptops limited to 2gigs of ram? mobile is the future, yet systems like the macbookpro, which can run multiple os's are hobbled by the memory limits. is it just architechture, design, or cost? or can it take more?

dot.

[JoeH]

Architecture, 2 GB is what the Core Duo processors can address without expensive addons. The Core 2 Duos with 64 Bit addressing can address more memory, but have not shown up in the MacBook Pro yet.

[Pops]

The limit will increase shortly after you've paid for your current laptop. That's a given corollary of "Finnegal's Law of Dynamic Negatives".

[vision63]

So it doesn't intefere with the upcoming "MacBook Pro Extreme." If the Core Duo processors can only address 2 GB without expensive addons, the maybe it wasnt' the best choice of processor since OS X thrives with more RAM.

[Silencio]

A 32-bit processor like the original Core Duo can, theoretically, address up to 4GB of RAM. The problem is that four SODIMM slots in a laptop end up taking up too much room, and 2GB SODIMMs are still inordinately expensive.

I read that the Intel-based iMacs (not sure if this was the Core Duo or Core 2 Duo model) can only address 3GB of RAM if you put two 2GB SODIMMs in there. Wonder if the same holds true for the laptops, too.

[JoeH]

The Intel iMacs that can address 3 GB have Core 2 Duo chips. In theory they could have more RAM, the limit is because of the memory controller used. As for 32-bit CPU's being able to address 4 GB, that is in theory only. Half the address space is reserved for such things as video, PCI slots, and other hardware. Indirectly they can use more memory, but that requires approaches like bank switching. Before servers had access to 64-bit CPU's, that was the they operated with more than 2 GB or RAM.

[Robo]

It makes no sense given that 2GB was the minimum amount of memory to make 10.4 usable (or at least a pleasure to use) on powerPC macs. With Rosetta, and some macs like the Mini and MacBook having shared memory for VRAM, 3GB is probably the new minimum. The new 512MB Mini in our household is actually slower than the old G3 600Mhz iBook that has 640MB when it comes to launching powerPC apps or having multiple apps open.