Welcome to community....
Screenshot is helpful but support logs will much more helpful... 
On your issue one core should be good to handle the VM. Check if spotlight indexing happens as soon as you launch any application inside Vm? If so, then performance issue is likely to happen. Clear caches from ~/library and /library and if needed re-index your entire hard drive.(it's a time taking process depending upon the data you have.)
note: shut down the vm and quit fusion before performing these steps.
Also I would suggest one core with 1 or 2 gigs of ram(depending upon the guest) should be good enough.
lastly if you have outlook configured then how many emails you have in your inbox?
I am sure you will get lot of suggestion here and hopefully we will find the root cause.... And if needed do upload the logs....(fusion menu>help>collect support logs)
thanks