By allocating a bigger number of cores from your CPU to VirtualBox you will improve the performance of the guest operating system running on your virtual machine and ensure a better, smoother user experience. You can edit the resources allocated to your virtual machine by changing the System settings of the software.

Step 1

Move your mouse to the top-right corner of your screen to reveal the Charms bar. Click "Search."

Step 2

Type "Virtual Box" and select that item from the list of search results to open VirtualBox.

Step 3

Click the "Settings" menu and select "System" to open the system settings for VirtualBox.

Step 4

Click the "Processors" tab. Adjust the number of CPU cores you would like to allocate to the guest operating system using the slider in the "Processor(s)" field.