[meshko]

I wonder if it would be possible to design a system which would power down some of the memory when not plugged to a power source. I do all my dev on an MBP and would be more or less fine if the memory-intensive things were only available when plugged in. That said, I don't really feel like 16gb limits me in any way except for doing data processing, but that should be happening on the cluster anyways.

[qb45]

Possible but hard because:

1. OSs are generally unaware of the details of memory controller configuration, everything is preconfigured by firmware. Apple's vertical integration could help here, but they would probably need help from Intel and it would work only in OSX.

2. It's not the case that if you install four 8GB sticks they will be mapped at 0-8G, 8-16G, etc. and the OS can simply move data from one area to another. For performance, data are striped RAID0-style across all modules. They would have to disable this.

3. I don't know if OSX supports non-identity VM-mapping of kernel memory pages. Linux for example doesn't afaik. Without this it's impossible to move arbitrary kernel objects because you can't find and update all pointers pointing to them.