We were talking about how Windows 10 substitutes the Microsoft Display Adapter Driver on older cards, but the GTX 950M isn't that old, so that wouldn't make sense to me.
Ideas:
-- I've noticed post processing effects in City of Heroes tends to misbehave more than recent games. For example, Depth of Field and Bloom I keep on the lowest settings in City of Heroes for a minor performance hit (60FPS looking at the ground, around 45-50 looking at the sky), where Star Trek Online, I can crank them to max on my 1050Ti and it keeps pace at 60FPS no problem. If I turn DOF and Bloom to full on City of Heroes, I get crashes. Bad ones where I need to restart. And it was a brand new card at the time.
-- OpenGL support tends to hop around from driver to driver when it comes to NVidia and AMD cards. Especially when most OpenGL chipsets were hovering around the 4.X spec and City of Heroes (if I remember correctly) is OpenGL 2.0 (Original Recipe)/2.1 (Ultra Mode). Most of the optimizations aren't headed in the 2.X direction these days. (You can buy a 1080 Titan, and still get the same performance in City of Heroes as the 950/1050 roughly.) If the performance change has been recent and you've updated drivers, you might want to consider if leaving a driver at an older version may help, or if playback on Doom and Skyrim is worth more attention and shrugging off Paragon Chat. That's a judgement call on your part.
That's what I can think of. If none of those are it, I'm all ears on further ideas.