I have a Quad Core i5 and a Geforce 670. I may not have a creme de la creme computer but I never had issues with any previous Day-Z version. I always used to have 25-85 FPS (depending on graphic details, cities etc.) Once trying out the experimental the frames drop and polygons get reduced. Almost like the game is trying to render the whole world (or as if my computer turned in to a peasant console).
I uploaded a video on youtube where you can see the symptoms.