The screen resolution is the number of pixels present surface area of screen. A resolution of 1680x1050 is a surface with 1680 pixels in width and 1050 in length. The screen resolution allows us to determine the aspect ratio (16:09, 16:10 ...) and the performance of the monitor.The size of a screen (in inches) and the screen resolution are the two factors to be taken in consideration. In the case you have a wide screen with low screen resolution, and this screen, this will result in a low quality display.
720p is a standard of high definition. 720 represents of its resolution: 1280 × 720 (no more no less), then as explained above a 720p screen will have 1280 pixels arranged horizontally and 720 vertically. The p means "progressive", the display is non-interlaced.
The standard 720p monitors normally come with the logo: HD Ready
A 1080p screen will give you a 1920 x 1080 pixels. The "p" means "progressive" just as for the 720p.
The standard 1080p monitors normally come with the logo: Full HD
The 1080i will be identical to 1080p in resolution but will differ in terms of image processing: processed images are interlaced, which may cause defects in the image.
The standard 1080i monitors normally come with the logo: Full HD
The best standard is the Full HD. If you have a choice between a progressive resolution and an interlaced resolution and money do not fail, opt for a progressive display.