In this video I’m testing NTsync (I call it anti-sync in the voiceover), a new Linux kernel feature that just landed with SteamOS 3.7.20, and why it might boost performance for Windows games running through Proton on the Steam Deck. The core idea is pretty simple: modern games spread work across a bunch of CPU threads (AI, physics, streaming, etc.), and those threads constantly need to synchronize. Up to now Proton has relied on fsync, which basically emulates the Windows-style behavior as a workaround by translating Windows sync calls into Linux ones. NTsync improves that by bringing Windows-style synchronization directly into the Linux kernel, so Proton can handle those operations more efficiently and cut CPU overhead. To see if it actually matters, I benchmarked Proton 10.0-4 (fsync) versus Proton GE 10-32 (NTsync) across several CPU-heavy games, with graphics pushed to the lowest settings to reduce GPU bottlenecks. I ran each benchmark five times with fsync and five times with NTsync to get more concrete results. The takeaway: in some games NTsync gave me as much as a 7–8 FPS bump (roughly 15–20% depending on baseline), and it seemed to work better in older titles. In other games the averages barely move, but frame pacing often looks more stable with fewer spikes—so it can feel smoother even when the FPS number doesn’t change much.