A player's OVR rating is mostly ascertained by the attribute coefficients (which attributes affect it and by how much). In the past few FIFAs, the International Recognition rating has had an additional 'boosting' effect on the OVR of real life players e.g Messi, Ronaldo and (most likely) Legends like Zidane, Figo etc. (NOT on VPs, scouted players, or created players (except when using the Creation Centre on the FIFAs compatible with it)). This is not there in FIFA 17, but there is something else going on.
I can say with a high degree of certainty after my testing this week that;
1) The coefficients' segment of the calculation plays exactly the same role as always. Also, the coefficients for each position are exactly the same as last year. EA must most likely change them every 2 years, but they DEFINITELY change them periodically.
2) Now to the differences. There IS a 'boosting' effect (definitely on real life players and most likely legendary players) but it has little or no correlation with the player's IR rating. This doesn't occur with every single player in the database but SOME REALLY LOW RATED PLAYERS ARE AFFECTED. Some players have none, others 1,2,3,4 etc.. 4 is the most I've seen so far but I've only tested a few. The ceiling may be higher than that.
3) Unlike the boosting effect from the IR rating in the past, this 'boost' is GIVEN FROM THE START and IT AFFECTS THEIR RATINGS FOR ALL POSITIONS YOU CAN EDIT THEM TO, BY EXACTLY THE SAME AMOUNT. You can see this by choosing a player (Use a secondary testing profile so you don't screw up your main profile's squads) and edit them by putting all their stats down to 1. In this instance, a player with no 'boost' would have an OVR of 1, which would be expected. Boosted by 1, their lowest OVR is 2 and boosted by 2, their lowest OVR is 3 etc.. This works for any affected player, even when changing their default position in Edit Mode.
4) This one will also concern sofifa.com. They display a player's Real Overall Rating which is essentially what you'd get from the coefficients alone. I fully expect them to do their own testing before taking the following at face value, but I've found that Messi is a 91 LW via coefficients, and a 93 LW in game. His boost is 2 FOR ALL POSITIONS. Ronaldo is also a 91 RW via coefficients, and a 94 RW in game. His boost is 3 FOR ALL POSITIONS. Luis Suarez, who is a 92 in game, when I put all his stats down to 1, his OVR rating dropped to 5 instead of 1, so he has +4 going on FOR ALL POSITIONS.
Again, you could use a secondary profile to test this, if you do, just edit Messi, Ronaldo et al to as many different positions as you can (when editing a player in game, wing backs (you get LB and RB) and wingers (you get LM and RM) are unavailable and Centre Forward becomes ST) and check what you get related to his Real Overall for those positions.
For those interested, Muller has a +3 boost going on. If he 'broke the system' with that, Suarez must have chewed it up and spat it out.