You'll need a Multi-Sync LCD, yours appears to be fixed at the 60Hz VGA standard. The Card's probably outputting a 75Hz refresh rate.
Quadra 700/900 graphics were groundbreaking for the Mac, being the first Magapixel implementation, but at a "measly" 8bits by comparison. It took three times the Quadra's 1MB max VRAM do so it at full color.
No, a NuBus card won't be faster than the Quadra 700's built-in video within its limited capabilities.The bandwidth limitations of NuBus make the cards slower at things like gaming or basic window scrolling, but those were never the purposes of multi thousand dollar NuBus graphics cards. More (TPD) and better (24bit depth) pixels along with QuickDraw acceleration (and DSP based acceleration for Photoshop filters for later cards) would be the stratospheric realm of NuBus Graphics.
Quadra 700/900 graphics were groundbreaking for the Mac, being the first Magapixel implementation, but at a "measly" 8bits by comparison. It took three times the Quadra's 1MB max VRAM do so it at full color.