Can you post a simple example...?
I'd like to see/experience this so I know what too expect..if I do the same using 2016.
Just upgraded to 2016 SP2.0 as i was having a .Step import issue on SP1.0, i have since discovered a memory problem also when using extend surface command.
All i had open was a really basic part using about 5Gb(total with emails/etc.) of my availiable 20Gb of RAM but it just suddenly bogged down and went really slow then solidworks resource monitor popped up saying i was running low and crashed out.
I've had this error happen 3 or 4 times since upgrading yesterday it works fine until you start getting over 10 or so surfaces then it just slows down to a crawl and crashes out each time
Report it to your VAR. I have had this problem nearly every release somewhere in the software, last year it was selection lines for weldments. I haven't seen it yet, but probably because I don't use surfacing often. I will test this end.