On multitasking -
http://www.jeffmixon.com/examining-build-prop-tweaks-for-android-ics-a-comprehensive-guide-part-1/
I note that we're running the ICS defaults for vm.heapsize and growth limit, appropriate for a phone with 1 GB of ram.
But we have less than a gig, as I recall, the S4 is mapping ram for i/o ports and also for the gpu.
In any case, we're all used to seeing 680 MB of ram, far less than a 3vo.
So now, I've changed my /system/build.prop like so -
# For ICS project, default 32m/48m
# 128/64 originally below
dalvik.vm.heapsize=96m
dalvik.vm.heapgrowthlimit=40m
And I am seeing two things -
One, ram now reports as 770 MB.
Two, my phone is screaming fast.
This is all very preliminary. Try at your own risk, make a nandroid backup first.
I would like to hear from anyone with lag issues willing to try this.
I'll be trying everything I can think of to stress test and will report back.
PS - tip of the topper to Wes and his report about having to kill Chrome. When I think of browsers, I think about core leaks and garbage collection, that's what gave me the idea.
I figured we had less than 70% of 1 GB ram, so a sloppy approximation of that on 64 gave me 40, and that article said the next should be double or more, so 96 sounded fair enough to me. That's how I chose my numbers, if anyone cares.