Well, I tried overwriting new clouds from the older AVP but with the same framerate, so i guess the problem is somewhere else.
Yes, I have pretty old laptop, but in older versions of KSP (like 0.90 etc.) it never dropped bellow 15fps...
So, backing back to the newer clouds, the prettier clouds...
(Also sorry for my english if you find something wierd, it's not my main language... )