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A comment on Linux ate my RAM . Parent comment

Re:Linux ate my RAM by csmuk on Monday November 11, 2013 @07:51AM (#6711322)
Why? All it does is make it go faster.
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Re:Linux ate my RAM by TBastiani on Monday November 11, 2013 @08:25AM (#6711434)
And drain your battery for no reason.
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Re:Linux ate my RAM by hansbogert on Monday November 11, 2013 @09:02AM (#6711584)
Do you have any proof of that? "Free" memory uses as much energy as "used" memory, there is no distinction in SD|DDR-RAM. And if the OS is smart, it only has to keep a simple index of memory pages still relevant. I'd argue that this has a measurable battery-hit.
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Re:Linux ate my RAM by runako on Monday November 11, 2013 @09:33AM (#6711736)
You're only accounting for the RAM power. Accessing the SSD costs power, too.
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Re:Linux ate my RAM by tedunangst on Monday November 11, 2013 @09:57AM (#6711872)
Then I think I'd rather Windows prefetched my programs while I'm plugged in so it doesn't have to do so when I'm on battery.
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Re:Linux ate my RAM by tanzam75 on Monday November 11, 2013 @11:29AM (#6712355)
> You're only accounting for the RAM power. Accessing the SSD costs power, too.

A typical modern SSD reads at 500 MiB/s, consumes 3 watts when reading, and 0.3 watts when idle.

A stick of DDR3 RAM consumes about 3 watts, just sitting idle.

The power consumption from prefetching is minor compared to that of the RAM.

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Re:Linux ate my RAM by jeltz on Monday November 11, 2013 @09:28AM (#6711715)
Reading from the SSD to laod it into RAM does drain battery. No idea if it is enough to matter though.
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