What I’m describing in my OP and follow up posts is a very specific issue I’m seeing and not meant to be indicating a general decrease in performance with SU12 (there are a few of those threads elsewhere!). On the contrary I’m actually seeing a (slight) average lowering of CPU usage (and so if I had vsync off I guess that would be an increase in FPS) BUT that appears to have come at the price of the significant spikes.
I’ve been careful to determine that these are not randomly occurring in time (I’ll never see them when stationary - parked at a gate for example) but are repeatable at the same geographic location. However, what is ‘random’ is there seems to be no reason why they occur where they do, i.e. in the middle of country-side miles away from major airports or cities. If you read my posts you’ll see I’ve eliminated the possible ‘non-deterministic’ causes of this I have control of, i.e. AI, live weather, cache on and off, network connection, etc. but I’m still no closer to understanding what is the cause. Hey, maybe its just the design of the software!