I used to have two mismatched monitors (Dell 2314 [1920 x 1080] and an older Dell monitor with 1280x1024). Now I have two matched monitors; two Dell 2314 monitors attached to an eDock with my Dell M4800 laptop docked to the eDock. My M4800 has a Nvidia Quadro K2100M video card installed with the Solidworks recommended driver version. "Mosaic allows hardware acceleration across multiple displays by treating them as a single large display." [However, Mosaic does not work with mismatching monitor resolutions] Will I get any performance improvement with SolidWorks if I enable Mosaic? I normally do not have SolidWorks span multiple monitors, my normal workflow has SolidWorks on one monitor while mail, web browser, excel, etc are on the other monitor.
All you'll get is a larger work area. The workflow you currently use is what I'd say the vast majority of us use.