Ok, in builder I created 4 X 9 He111H flighs for a total of 36 bombers all pretty tightly grouped.. I then added 6 Spitfires and 6 Hurricanes.. at about 6000M starting just off the coast of England.. attacked and followed them inland.. at 1920X1200 my fps remained in the mid 40's until I entered the box and lots and lots of AI gunners shooting at me.. at the low point my fps was down to 50 for a blink..but mostly bottomed out at 30fps.. completely fluid and playable..
As weak as AI gunners seem when there are just a few..36 He111's worth was QUITE lethal