10 seconds of recording UI crashes iphone 7plus but works on 12 

I'm using the Record View example in demos. On 7+ my animated view (upon finishRecording) doesnt finish but crashes due to memory pressure (memory usage goes from 100MB to 1GB+) and then crashes.
The same works fine on 12. 
Is there something inherently missing (hardware wise) on 7 plus? Like metal support etC? 