Hi guys!
first thanks for the answers! After my nightshifts I continue with investigating in the frame drop issue described before.
Just started a singleplayer with PHK only and beyond multiplayer activities - and yes it's much better but still available. Started with over 100 fps with 99% GPU workload durable. After ~30min my rig holds 40 fps by about 15000 units score und > 400.000 military and economy score. With substrate insane AI I assume the game would crash at this point with <10fps. However in this PHK only game the CPU/GPU workload dropped to around 40-50% and the CPU started to reduce the frequency at which point I quit the game.
@ RomeoReject
Usual load temperatures CPU ~49°C and GPU ~ 45°C. The CPU is cooled by Alpenföhn Olymp and the GPU by Arctic Cooling Accelero Extreme IV. I'm monitoring many rig real time data with the keyboard internal display from logitech G510. AIDA64 sends all the data to the keyboard display.
So theoretically the temperatures shouldn't cause the issues.
@ Ticktoc
Yes I also expect raising workload by high demands but the opposite occurs. I assume anything prevents further forcing the CPU workload. Maybe any kind of driver overhead or anything like that? Strange issue.... cause at the beginning of any game or in bechmark scenes all works fine.
Just for a few minutes I continued with campaign escalation (didn't finished it yet 
). The maps containing partially over 6 enemies some of them substrate. With military and economy scores around 15000-20000 (so lower than any multiplayer game) the massive drop began. Finished the maps with ~20fps by 20-30% CPU/GPU workload.
BUT during switching around DX11 / DX 12 / Vulkan just noticed that vulkan has lower "maximum" FPS than DX 12 though but much more FPS stability and lower CPU usage at all. The CPU is able to hold higher minimum FPS and frequency reductionoccurs significantly later but is still available. Maybe the (however it's called) "game engine" is limiting and has issues with handling such high amount of units?
