Does Unity 2d use fewer system resources than Unity 3d? If it requires less in terms of system resources, would switching to Unity 2d increase the battery life of my Laptop?
The battery life issue is due to a regression in the linux kernel. It doesn't have anything to do with unity.
I'm sure unity 3d's effects have some small negative effect compared to unity2d, but the best thing to do at this point is wait for a kernel version that solves the problem.
AFAIK kernel 3.0 still has this problem, but to a lesser degree.
Definitely. Apps that are resource-hungry increase load on the hardware side (processor, bus activities, memory allocation, etcetera) and these lead to increased power consumption. If you want to optimize you battery life, I would suggest these things:
Use a minimal GUI without as many fancy effects. In 11.04 you can select Ubuntu(Classic) during log-on.
Turn off your wireless adapter and bluetooth adapter. Surprisingly, these adapters can suck out most of your battery life. Only turn them on when you are using them.
Dim the screen to the lowest level that's practical and comfortable.
Don't work in such a way that multitasking of processes in necessary, unless you need to do so.
Turn off sound or use earphones. Using built-in speakers requires more power.
Try this out and you will be surprised at how long your laptop battery can last (provided the battery is not dying).
Hope this helps.
I think this really depends on your hardware, and the way you look at "less resources". If we are just talking about resources such as overall hardware, Memory and CPU utilization, leaving the question of battery aside, then your hardware needs to be considered.
If you don't have an external (to CPU) graphics card, then the statement Unity 2D uses less resources makes sense.
However, when you do have a pretty decent external graphics card, why let those resources chill at the side? Using Compiz (Unity 3D) utilizes resources available to you that otherwise would just sit there and be wasted. While in one point of view it's using more resources, but on the other hand it moves some burdens to your GPU, so it actually uses less resources on a purely CPU and memory point of view.
Just look at Phoronix's Desktop Manager Analysis
Same computer running Compiz and Metacity, and they perform about the same. So why not get the fancy effect?
in the end, it's how you look at it. And there's probably no way to know for sure which one is better on your setup until you do a test on it.
Actually, I used powertop to measure the number of wakeups, which is an indicator of power usage. Unity 3d, classic with effects, classic without effects are more or less the same as far as wakeups are concerned. Unity 2d seems to be less efficient - may be due to early stage of development. KWORKER, whatever this process is produces the most wakeups and is a process I haven't seen before.
You should check out the jupiter power management applet, it had given me a couple extra hours on my battery.