I am having the same problem. Before i downloaded the update i could run all the 2017 sx tracks at 115-125 fps with no problems. Now the highest fps i get on any tack is 55-70 fps.

Before i downloaded the snapshot i could play the stock tracks at 125 fps (and the 2017 sx tracks between 110-125 fps) now after downloading the snapshot the most fps i get is in the 70's. Any help would be very appreciated.

Fun track. The sand is very fun. It is a little short, would be great if there were a few more sections.
Thank you for the track.