Can you give the monitors part number? It may be a 75hz monitors but it may have a long refresh rate. 2ms, 5ms, 7ms, and 10ms are very common to see. Lower is better. If it is 10+ then gaming will suffer. If you went from a lower resolution to a higher one, then you may have lost some FPS. If you simply have a larger screen and the same resolution as before, try to enable vertical snyc and up your anti alising.