Even with variable resolution, it's sometimes locked to multiples. Take Dolphin, for example: the largest resolution among its options that can fit into my screen is 2560×2112. However, fullscreen mode will try and scale that up to 2618×2160. I end up having to use Windowed mode or third-party apps such as Lossless Scaling to achieve my desired output.For older games with a set resolution this is the same route I like to go. For anything where resolution is variable but not widescreen I go with black bars of sorrow.