[chongli]

An adult male needs around 2500 kcal per day. This works out to 2906Wh. The battery in a Nexus 5 is around 8Wh, for comparison. The question then becomes: how many hours would the battery last running the Komodo 9 engine full-out?

That would be an interesting matchup. I bet a grandmaster could play slow enough to kill the battery on the phone. A human could go a day without eating no problem. There's no way the phone could go a day without charging while running 100% CPU.

[gus_massa]

A normal chess match last about 4 hours. If we divide proportionally the energy of the day, that will be about 400Wh. I remember a factoid that says that the brain consume the 20% of the energy of the body at rest (less % while running) (more % while thinking?), so if we cut the unnecessary stuff [0] that will be 80Wh, i.e. 10 batteries. Probably the phone is more efficient.

[0] Don't try this at home.

[chongli]

So 10 batteries... how long do you think the engine could last on one battery? Then we multiply that number by 10 and see if it's less than 4 hours... hmmm

[DannoHung]

Why on earth would the phone be running the chess engine 24/7 ? It only has to run the engine when it needs to select its next move.

[taftster]

Traditional chess applications are "thinking" while waiting for you to move. That's not to say they can't be sleeping while waiting for your move, but it would just delay the game tempo and possibly (slightly) limit the overall competency of the chess AI.

[noir_lord]

Not slightly, greatly.

Speculative move generation of a chess engine on opponent time is a huge part of the overall strength especially when the engine can see a forced move therby collapsing the tree.