If you are on Windows 7 and experiencing degraded performance with HOST network (browsing other computers in the physical network has become dramatically slow, transfering files from or to other computers have become painfully slow and the transfer rate is just KBs while your connection is 100/1000MBPS) then be assured, the virtual adaptors installed by these virtual boxes are playing off.
Detailed explanation from VMWare KB article could be found here (This KB article is pretty old, however the issues handled are same till date, so don’t get confused)
To get over with this issue, you may go ahead and disable the virtual network adaptors installed by VMWare or Oracle/Java VirtualBox application(s).
Edit the virtual appliance network property and selected “Bridged” and optionally “Replicate physical network state” (check image)
Workaround status: Fully checked and confirmed.