Hi, well thats what you get for patching….
Hmm, you seem to think harddrive access is causing the slow down?
The patch cannot have reduced the discs access speed physically, must be software accessing causing the slow down or new read write procedures.
I would check taskmanger and go back to only basic services and programs only, check memory and cpu utilisation. At a guess, you have no physical RAM left and are using the page file, this will cause the slowdown. Ring microsoft they will probably have heard it a thousand times. Good luck.