You are correct the state of Massachusetts is not a part of the Drivers License Compact (DLC) which allows member state to transfer information regarding out of state tickets back to the state the driver was licensed in. Though MA is not a member of this Compact, their Registry of Motor Vehicles has arranged to share driving records and violation information with other states.
So it would appear that the MA RMV or MA courts will send the speeding ticket information to Rhode Island once you are convicted of it.
Rhode Island state statutes say that the Rhode Island Division of Motor Vehicles (DMV) is authorized to take action against the license of a RI resident if they receive notice of an offense in another state. For example if RI is notified of an offense in another state that would cause your license to be suspended, if the violation had occurred in Rhode Island, than the RI DMV would suspend your driver's license.
The statute does not make it clear if Rhode Island will put all out of state citations on your RI driving record or assess points, so you should check with the RI Division of Motor vehicles to find out for certain what they do after being notified of an out of state speeding ticket.
If the Massachusetts speeding ticket, is placed on your driving record, than you insurance company would see it. Check with your insurance company to find out how they rate for speeding tickets since rating systems differ from one insurance carrier to the next.
If it is your first moving violation in 20 years then it might not affect your rates or only cause you to lose a safe driver discount. But your insurance company will have to tell you their specific way of rating for moving violations and if your rates will rise by how much. If our insurance rates rise, do some car insurance comparison shopping.