Resolution of the screen? If it's the same as the monitor then just RMA the monitor.
What task are you doing that made you see the pixels?
If watching a 240p video on a 1080p monitor fullscreen of course there will be visible pixels.
haha..this i know...
but i am just surfing net etc.normal usage. weird thing is it only affect one side of the monitor..and it flicking..
If you have a second computer or laptop, test it as a second screen see whether problem still persists. If yes, monitor most likely faulty. If no, might be GPU.