Parallels notes that these operating systems currently run “really slow” due to the overhead required for translation. Windows takes between two and seven minutes to boot, depending on the speed of your Mac, and “the responsiveness of the operating system is low.” Rather than attempting to multi-task, Parallels says you should close the app you’re using before trying to open another one.

This reminds me of the old days on PowerPC.

The technology preview is currently limited to certain 64-bit versions of Windows

So very specifically it’s amd64 (which makes sense, now that Macs won’t run 32-bit software).

Wish the article headline was more specific about that