Surfer's EP is still superior, but it's a lot closer. Ring allows Supes to counter energy drain or kryptonite radiation, enough that it's a non issue.
Supes is a little stronger and may have a combat speed advantage. I think this goes like Thor vs Surfer....Supes wins.
Actually it's worse. GL ring durability + Supes means you won't be able to hurt him.....Surfer is in trouble
The ring should allow Kal to take energy absorption and Greek K fine, and so he can focus on getting close into Norrin and make this into just what Thor tends to do to him, hammer time!