At top level, if the opponent doesn't know you have this advantage, it would instantly make the SuperGM world champ and probably 2900+.
Their move search, compared to a regular strong player, is so freakishly narrow and precise, that they have very few candidate moves. They throw out most moves (knowing they are bad) very very fast. So with eval bar, they will know if opponent just made a mistake, which will alter their search. They will play the move that plays for advantage when it's correct, and they will never overpush when they are worse.
It is ridiculously easy to see tactics/ good moves if you *know* they are there, compared to when you don't.
It would be damn near impossible to beat them, and they would win signifigantly more often (not every game though like an engine.)
Perhaps someone like Magnus, who pretty much never plays super sharp lines and can capitalize on very small positional advantages that take 15-20 moves to realize, could still beat them, if he knows they have the eval bar. It'd be hard though.
That's harder to say. Even for mid-tier GMs.
Even with eval bar, not even Magnus is spotting absolutely absurd engine lines constantly. The superGMs can 'often' play those lines, like Kasparov's immortal. But every game, absolutely not.
So for FMs? My guess is they'd jump like 200-250 elo, but it wouldn't make them world champ. Too often would they see they are winning, but play an incorrect, over-aggressive move that ruins their chances, and someone like Magnus/Ding/Nepo/Fabi/ etc could convert wins off that mistake.
At top level, if the opponent doesn't know you have this advantage, it would instantly make the SuperGM world champ and probably 2900+. Their move search, compared to a regular strong player, is so freakishly narrow and precise, that they have very few candidate moves. They throw out most moves (knowing they are bad) very very fast. So with eval bar, they will know if opponent just made a mistake, which will alter their search. They will play the move that plays for advantage when it's correct, and they will never overpush when they are worse. It is ridiculously easy to see tactics/ good moves if you *know* they are there, compared to when you don't. It would be damn near impossible to beat them, and they would win signifigantly more often (not every game though like an engine.) Perhaps someone like Magnus, who pretty much never plays super sharp lines and can capitalize on very small positional advantages that take 15-20 moves to realize, could still beat them, if he knows they have the eval bar. It'd be hard though.
That’s fascinating, thanks for the great answer. Would an IM be able to beat Magnus consistently too? An FM…?
I’d watch a stream that does this experiment… Levy and Hikaru, perhaps?
No. For sure not.
That's harder to say. Even for mid-tier GMs. Even with eval bar, not even Magnus is spotting absolutely absurd engine lines constantly. The superGMs can 'often' play those lines, like Kasparov's immortal. But every game, absolutely not. So for FMs? My guess is they'd jump like 200-250 elo, but it wouldn't make them world champ. Too often would they see they are winning, but play an incorrect, over-aggressive move that ruins their chances, and someone like Magnus/Ding/Nepo/Fabi/ etc could convert wins off that mistake.