> All the web browsers used their default configuration, without any add-ons or toolbars installed.
My raw, untested guess is that using Firefox with some strict adblocking/flashblocking etc. tools might reduce its power usage due to less HTTP requests, less CPU/GPU time wasted (though OTOH the add-ons may increase the CPU load to do their job, so it's non-obvious).
One large factor is forcing the system to tick every millisecond instead of every 15.6 milliseconds, which both Firefox and Chrome are currently doing on my computer.
Is there any way to make Windows ignore those requests?
Tickless by itself doesn't guarantee that the system won't be woken up periodically by an application timer. It simply guarantees that the system won't wake up needlessly if there are no timers to serve.
Timer coalescing, which I believe Windows also implement, does help by both setting a minium resolution to timer frequency and making sure that timers wake up in batches.
