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I wonder if there would be significant environmental implications if everyone switched to full disk encryption... Does this impose a significant processor load

I wonder if there would be significant environmental implications if everyone switched to full disk encryption... Does this impose a significant processor load and does that translate to greater power consumption?

justanotheratom 15y ago
I wouldn't worry too much about it. There is a fixed CPU overhead, but negligible. http://www.tomshardware.com/reviews/bitlocker-truecrypt-encryption,2587-9.html http://www.tomshardware.com/reviews/bitlocker-truecrypt-encr...
sitkack 15y ago
An idling CPU and a slightly loaded CPU use about the same amount of energy. I think my Q6600 quad used 190W @ idle and running full tilt cpu (ray tracing) it was using 220W. For FDE it depends on how much IO you are doing. I doubt it will make even a 0.01 difference in your daily power consumption.
- mikeash 15y ago
  I don't think so. On my laptop, fully loading the CPU takes it from silent to screaming fans in about two minutes. That's clearly a big change in heat production and therefore power consumption.
  - sitkack 15y ago
    You should use a kill-a-watt and measure it. Probably less than you think. Laptops already on the edge of their thermal envelopes, anything above their low steady state (browsing, listening to music) will cause the fans to spin.
    - mikeash 15y ago
      The battery time remaining will also drop by a factor of 4 or more. This is large enough that I don't think a more precise instrument is needed to determine that the effect is significant.
      - sitkack 15y ago
        If I have time this weekend I will pop the battery on my macbook and do an erlang compile on an encrypted sparse image both on the rotational drive and the ssd. I'll report back on how much energy was consumed for (encrypted,non-encrypted) x (ssd,rotational) batteries derate rapidly as the current draw goes up. They are not linear. For my own edification it would be nice to know what kind of energy hit encryption takes on both storage mediums.
        mikeash 15y ago
        I would definitely be interested in hearing. I don't expect that the overhead of encryption will cause much additional power draw, simply because encryption doesn't require all that much CPU power. The stuff about fully loaded CPUs was wandering off into the theoretical realm about CPU power consumption variance in general. For whatever it may be worth, I couldn't find idle power consumption for my notebook's CPU, but it is possible to come up with a worst-case estimate by taking the battery capacity and dividing by the runtime. Apple specifies "up to" 7 hours. While that is of course hard to achieve, I think it's fair to use that figure when looking at idle power use. The battery is 50Wh, so we can figure that the computer as a whole is using at most about 7W when idle. The i7-2677M CPU is specced to use up to 17W all by its lonesome when running flat out, so that's a substantial increase, especially when you take into account the fact that the base 7W idle-ish consumption is for everything in the computer, not just the CPU.
brc 15y ago
Simple answer : no. Even at massive scale where everyone did it, the tiny, tiny differences in power consumption wouldn't be a rounding error in power generation. Power stations are built to supply x amount of energy for y time. They aren't like a car engine where switching off the air-con makes a noticeable difference. This kind of meme gets going because of the campaign to switch appliances off at the wall, thinking it is going to make some type of differences. Every analysis I have ever seen is that (1) the difference is so small it makes no difference and (2) whatever minute drop in demand is found will quickly be used up in industrial users expanding consumption into the lower demand period. Just running one arc-furnace or aluminium smelter for 1 hour longer is going to negate most domestic level fine shavings like switching the TV off at the wall. Mostly this stuff is promoted to make people feel like they personally are involved and making a difference.

justanotheratom 15y ago

I wouldn't worry too much about it. There is a fixed CPU overhead, but negligible. http://www.tomshardware.com/reviews/bitlocker-truecrypt-encryption,2587-9.html http://www.tomshardware.com/reviews/bitlocker-truecrypt-encr...

sitkack 15y ago

An idling CPU and a slightly loaded CPU use about the same amount of energy. I think my Q6600 quad used 190W @ idle and running full tilt cpu (ray tracing) it was using 220W. For FDE it depends on how much IO you are doing. I doubt it will make even a 0.01 difference in your daily power consumption.

mikeash 15y ago
I don't think so. On my laptop, fully loading the CPU takes it from silent to screaming fans in about two minutes. That's clearly a big change in heat production and therefore power consumption.
- sitkack 15y ago
  You should use a kill-a-watt and measure it. Probably less than you think. Laptops already on the edge of their thermal envelopes, anything above their low steady state (browsing, listening to music) will cause the fans to spin.
  - mikeash 15y ago
    The battery time remaining will also drop by a factor of 4 or more. This is large enough that I don't think a more precise instrument is needed to determine that the effect is significant.
    - sitkack 15y ago
      If I have time this weekend I will pop the battery on my macbook and do an erlang compile on an encrypted sparse image both on the rotational drive and the ssd. I'll report back on how much energy was consumed for (encrypted,non-encrypted) x (ssd,rotational) batteries derate rapidly as the current draw goes up. They are not linear. For my own edification it would be nice to know what kind of energy hit encryption takes on both storage mediums.
      - mikeash 15y ago
        I would definitely be interested in hearing. I don't expect that the overhead of encryption will cause much additional power draw, simply because encryption doesn't require all that much CPU power. The stuff about fully loaded CPUs was wandering off into the theoretical realm about CPU power consumption variance in general. For whatever it may be worth, I couldn't find idle power consumption for my notebook's CPU, but it is possible to come up with a worst-case estimate by taking the battery capacity and dividing by the runtime. Apple specifies "up to" 7 hours. While that is of course hard to achieve, I think it's fair to use that figure when looking at idle power use. The battery is 50Wh, so we can figure that the computer as a whole is using at most about 7W when idle. The i7-2677M CPU is specced to use up to 17W all by its lonesome when running flat out, so that's a substantial increase, especially when you take into account the fact that the base 7W idle-ish consumption is for everything in the computer, not just the CPU.

brc 15y ago

Simple answer : no. Even at massive scale where everyone did it, the tiny, tiny differences in power consumption wouldn't be a rounding error in power generation. Power stations are built to supply x amount of energy for y time. They aren't like a car engine where switching off the air-con makes a noticeable difference. This kind of meme gets going because of the campaign to switch appliances off at the wall, thinking it is going to make some type of differences. Every analysis I have ever seen is that (1) the difference is so small it makes no difference and (2) whatever minute drop in demand is found will quickly be used up in industrial users expanding consumption into the lower demand period. Just running one arc-furnace or aluminium smelter for 1 hour longer is going to negate most domestic level fine shavings like switching the TV off at the wall. Mostly this stuff is promoted to make people feel like they personally are involved and making a difference.