poor optimization for laptop GPU, excellent on desktop

[B_Montiel]

I’d also go for heating issues. I’m playing on a desktop with an old i750 clocking at 2.67 GHz. I manage to keep its temperature steadily below 50°C. With good gpu and 8Go of RAM, I usually get over 100 fps. And I’m using usual low config. I noticed strong performance decrease when we had 35°C days where I lived, so I’d not be surprised that cpu automatically downclocked itself.
UE3 is indeed a strong cpu performance eater but as long as your temperature stay at acceptable level with the charge, it should be fine. Don’t forget that when UE3 got released multi cores computers were not mandatory in the average personal rig.