Seems likely. It only stutters on Windows - run it through Proton on Linux, where it's translating it all to Vulkan, and it's silky smooth. Maybe off by a frame or two as well of course, but it's pretty much locked to 60 fps in either case on my machine and can't really check. DirectX seems quite bad for hitching when a new shader is loaded - they'd all be pre-compiled on a console since the devs know exactly what the target hardware is, so if you don't rewrite your engine on Windows to accommodate it, then you'll have problems.