Hibernatning RAM

[Arjan van de Ven]

Magnus Fromreide wrote:
> On lör, 2008-03-15 at 08:43 -0700, Arjan van de Ven wrote:
>> Magnus Fromreide wrote:
>>> Hello.
>>>
>>> I have two memory modules in my computer (.5G+1G) but usually I use a
>>> lot less memory than 1G that so I would like to ask:
>>>       * Is it possible to tell the system to shut down part of the main
>>>         memory in order to save power?
>>>       * Can I do it from Linux?
>>>       * How?
>> this is not an easy task. The way dram normally works is that both dimms
>> get interleaved over memory (so alternating pieces of the memory come from
>> different dimms) for performance reasons......
> 
> This sounds complicated when there are differently sized and timed dimms
> involved.
> 
>> however this also means it's not possible to just turn one dimm off.
>>
>> there is some research being done on systems with many dimms, to make the interleave less
>> (say from across-8 to across-4) and then be able to turn a few dimms off, but on a 2-dimm
>> situation... I've not heard of that yet.
> 
> Ok, thanks for telling anyway, this is quite interesting.
> 
> Do you know where I could find mre information about this?
> 
I don't think it ever made the light of day other than a few patches on lkml that people hated.
No matter what it needs a special bios, and probably even a chipset thats capable of doing this.