whats the best resolution settings for dual displays?

The best resolution is the native resolution. If you are cutting the resolution less than that to avoid stutters in your audio, that would be a kludge or a workaround. It is surprising that such a minor change in resolution would resolve the issue. If page faults are not interupting audio processes on your DAW, then you can ignore them.
 
Page faults indicate that you are using virtual memory i. e. accessing the windows swap file on a hard drive. More physical memory, or less memory intensive processes will tend to reduce page faults. If you are finding the problem with video at higher resolutions, that would tend to indicate that you might benefit from a more efficient video card or one with more on board memory. Do you have a dedicated video card, or is a video chip sharing system memory?