This probably depends greatly upon whether your machine has discrete graphics or not. On Macbook Pros with nVidia graphics like my 2014 higher-tier Macbook Pro, there is a dramatic loss in battery when the discrete graphics kicks in. However, most Macs sold now don't have discrete graphics because the Intel integrated graphics is honestly pretty decent nowadays for most tasks. The difference is 3 hours of battery and 8+ for me.
Google Chrome, similarly, tends to drain my battery a lot, and that alone has encouraged me to go to Safari on Macs.
Can anyone tell me why this isn't an inbuilt feature of OS X? Preferably in the 'Energy Saver' pane of System Preferences, e.g. while on battery power, only use integrated graphics.
There was a discussion that sometimes it is better to run a task quick on GPU than to run it for longer time on CPU. Would be cool if someone could try to prove this or inverse. :)
Maybe it'll be different in Metal-backed El Capitan, but my experience so far has been that the discrete GPU universally degrades my battery life. I'm glad I have it though; sometimes I need it, but it'd be nice if I could just disable it completely most of the time.
Ehm when we talk about Vmware Fusion and discrete Graphics you are obviously wrong. You could change the graphic mode in Vmware Fusion, so that you save lots of power..
I get increased battery drain with VMWare Fusion without even turning a VM on for similar reasons as just starting Google Chrome - it causes a switch to discrete graphics merely by starting the program up with no clear pattern of releasing it. It has rather little to do with a VM workload in my observations. If I completely disable discrete graphics, that stops the switch and the subsequent battery drain. However, I lose my external graphics output when I do that evidently, so if I need to use my external monitor, I will lose battery anyway.
I can see the graphics switch happen with gfxCardStatus notifying me. The process occupying the GPU is from Fusion plain as day (I think it's vpx agent?). This happens with nothing else running. This switching is one of the known quirks with OS X after years and years now.
Also, older versions of Fusion may have been less careful about avoiding graphics modes that potentially cause graphics acceleration to kick in and maybe more recent versions than mine do better (still on 6 because I'm a cheapskate).
Google Chrome, similarly, tends to drain my battery a lot, and that alone has encouraged me to go to Safari on Macs.