When I open KVV window fps drop from ~40 fps to ~20 (its ok).
Until I have to re-load the vessel fps stay low (closing KVV window dont increase fps).
Same problem:

mrBlaQ:
It gets very choppy and slow right after opening the KVV window the first time in VAB. It stays choppy even after closing KVV. I have to re-load the vessel for it to clear up. I'm guessing the shaders are being loaded on every frame?

@CubixSystem

Please try this beta release