Strange effects in FS9 after installing Nvidia driver 285.62

Hello all,A few days ago I installed the Nvidia 285.62 driver, replacing 275.33 (never installed 280.26). As usual for me, the installation was done via the 'express' method. Subsequently in FS9 the fps showed wild variations ('V' op to 40%), and frequently dropped to around 9, obviously causing lots of stutters. After rolling back to the old driver everything was normal again. This is very odd and since nobody as far as I know has mentioned any problems with the latest version, I've got the feeling that the culprit lies at my end, but I haven't a clue where. Could it have something to do with the new Inspector? I've read somewhere that the old Inspector should be deleted before installing a new one. Any suggestions would be very much appreciated.Kind regards,René