StevieT: I've found my laptop freezing every so often, without any error message appearing in the System Log.
Also, Facebook loads very slow (images, the side bar, notifications, messages) both in Firefox and IE, yet Facebook loads fine on our Windows 8 PC at the same time - which rules out a connection problem.
Both issues started immediately after installing 8.1.
Anyone else having these issues on Windows 8.1 Pro?
I had a cycle of problems, after 8.1 I had to wait for a BIOS update from Sony, then after applying that I had to apply more updates from MS. It's running now, but who knows after the next one.