Default Netflix stuttering on battery.

Once I plug it in to charge, stuttering stops. This is leaving me to think it's a phone issue. I337M, CM KitKat Nightly, Feb 17, Ktoonz kernel, Ktoonsified 2.1 settings.

Voltage issue? Any ideas?
Samsung Galaxy S4 SGH-I337M
Former:Samsung Galaxy SIII I747 (Telus)
Former: Nexus S Rom: XenonHD v2.0