For those of you who had the “pleasure” (okay, slight sarcasm there) of watching me in the SharePoint Ignite materials talk about distributed cache, you may recall that our guidance at the time SharePoint 2013 shipped was that you should not patch AppFabric on SharePoint servers independently – meaning that if it needed patching the expectation was that it would be delivered with a SharePoint patch and AppFabric patches should not be applied. Since that time, we’ve reviewed the plans there and have decided that in fact patching AppFabric directly is how it should be managed going forward. So you will see a KB article here that describes doing just that: http://support.microsoft.com/kb/2843251.
This has been causing a bit of confusion recently so we were lucky enough to get final clarification on this so folks can move forward. That being said now, you can (and should) go look for CU4 for AppFabric, because it has some bug fixes and performance improvements that will help you out in SharePoint land. You can find that at http://support.microsoft.com/kb/2800726.