Arjan, if you are having speed related issues, please create a new post, specifying exactly what is slow, which OS version, which Sublime Text build, how large your project is, if indexing is currently occurring (i.e., multiple sublime_text.exe processes, and a percent complete indicator in the status bar), and if the files are on a local or remote file system.
FWIW I haven’t seen any Windows related speed issues, irrespective of project size.