In the normal cases the only concern with demanding sse on i386 by default is old CPUs which don't support it (which is probably less of a concern these days). But in Wine case that is a matter of compatibility, games have issues / bugs which are mitigated by the fact that dlls on Windows use x87 in dlls. Re-Volt game will leak x87 stack in its own code but will get away with that because it is doing ddraw calls using x87 that would inevitably reset fp stack for it from time to time (breaks if enabling sse). I don't have an example in hands rn but I suspect there will be more of less exotic issues when some game will depend plainly on x87 rounding / else mode affecting things in the same ddraw. -- https://gitlab.winehq.org/wine/wine/-/merge_requests/10953#note_140725