Speaking from experience, the Sony 900H has infinitely better viewing for sports than any Samsung on the market currently, if you have the motion processing off. The reason your old Samsung looks “better” than your Sony is because your older Samsung has a lower refresh rate than the Sony. If you go into the settings and turn off the motion processing it’ll just show raw data; exactly like your older Samsung does. What the Sony is doing at the moment is trying to “guess” frames and insert them so it’s 120 hertz, in theory this would be smoother than the raw data but nothing ever works that way, your older tv didn’t have to do since it wasn’t 120 hertz. The newer Samsungs you can’t actually turn off all of the motion processing (not to mention Samsung’s motion processing isn’t even good to begin with, at least Sony’s helps some of the time) which gives it a constant stutter.

Edit: Action Menu -> settings -> Display and sound -> picture -> advanced settings -> motion -> motion flow -> off (What it sounds like you would like)

Tweak this however you like to make a picture that looks good for you I’m one of the few people who actually likes the motion processing, so I actually increase everything, but it’s all a preference thing.

Have you turned off any kind of smoothing effect?

Go into the picture settings...