I'm generally not in favour of moving things off the SSD. It's generally done for the wrong reasons IMO. People tend to want to move frequently used thinsg to save wear on the drive. Each to their own but it seems strange to me to buy something to make your computer faster and then not use it for the most frequently accessed fiels - which in my view would be the ones I want fastest.
This one however is a little bit different. The WIndows installer cache. It keeps a local copy of everything you install so you can later uninstall it. It is therefore used very infrequently and for most programs, probably never. If you delete them though it makes a mess of add/remove programs (I have done this on a past install 
)
In my case, this rarely used folder that I can't delete is 2gb! So I reckon this is one folder worth moving to your mechanical driver. The folder in question is c:\windows\installer
Move this folder to say your d drive so it is now d:\installer
Now startup an administrative cmd prompt (type cmd in the search box, right click and choose run as admin)
Now type
c:
cd \windows
mklink /d installer d:\installer
This will create a directory shortcut between where Windows expects to find this folder and where it actually is.
And while we're saving space and have a command prompt open, if you haven't already done so, disable hibernate if you don't use it to free up as much disk space as you have ram. The command for that is as follows:
powercfg - h off
With this and my previous post... can you tell I'm running out of disk space??
