You simply have to allocate more CPU and RAM into NOX. This can be down by opening NOX Settings > Advanced. I would recommend switching performance to high, but you can customize it to your preference. Upon completing all the steps, if you NOX Emulator is still running slow, switch the graphics rendering mode found at the same place.
- Japan: held from March 29 to June 30, 2016, announced on March 3, 2016
- Australia and New Zealand: held from April 25 to June 30, 2016, announced on April 7, 2016
- United States: held from May 25 to June 30, 2016, announced on May 16, 2016