alt Hacker NewsFrom my reading, it will be replacing a user-space sync emulation handler with a kernel-space sync module. Generally, kernel space will be faster or more efficient than user space. Whether this matters in any appreciable way (more than 1% improvement) in reality will have to be seen.
It's more that FSync was close to but subtly different from the Windows synchronization primitives when used in certain specific ways and NTSync is a 100% accurate implementation of those same exact Windows synchronization primitives. It should resolve hitching and other minor issues in older games, especially.
Basically it will have no performance improvement, in some cases minor degradation, but it resolves some compatibility issues with older multi-threaded programs.