4.4.5? Do you mean 4.5.2 (that was the one on the CD last I checked).
And then the same problem when booting the older kernel after the upgrade?
If that's the case, the only thing I can think of is the microcode; it gets updated when you update the "linux" metapackage, and unlike the kernel, firmware blobs live in a common directory and get overwritten with updates. (package on CDs is 20160402_1, current pkg is 20161206_1)
(unless you happened to notice if any other packages got pulled in with the linux update)
short of pulling the Kaveri firmware files from the CD (there are 16 of them) the only other thing we can do is look to find out if any module options are known to resolve this. although I suppose that is an option, except every update would overwite the files, and you'd have to put them back. Not a good way to work, though it may be a decent test.
Note Kaveri is one of AMD's APUs (radeon chip together with CPU). Knowing that may or may not be helpful in finding the actual cause/fix...
If you can ssh into your laptop when it's frozen like that, see if dmesg tells you about any errors (recent kernels now require root privs when running dmesg, so use root, or sudo).