My VDU is 17" and a Packard Bell one at that and is capable of a display of 1280x1024 with no problems. (My normal mode is 800x600 or 1024x768) It does not flicker etc. The only way you can damage the monitor is by setting the refresh rate beyond the maximum that it is designed for. My maximum is 120Hz for 640x480, 100Hz for 800x600 and 1024x768 etc.
To find info about your refresh rates, I suggest you READ YOUR MANUAL! Also, you may find some info on the label on the back of the monitor.