Hi, i have a Benq GL2450HE and a club3D R9 270 CONNECTED with dvi-d

and my screen is not sharp, PICTURES and text are pixelated ...

(motherboard MSI A78M-E45) Wrong drivers...or the card is failing...how old is it ? ?* Could also be the display itself failing but Im leaning towards what patio said. But if you have HDMI on that card and a TV etc, Id connect to that and see if you get same results. If results are the same then its a driver or video card issue, if different then its a bad DVI cable or Display

Pixelated usually means the video card BTW or an issue with shared memory and RAM issue with refresh of memory addresses etc to where you have artifacts. 9 times out of 10 its a bad video card.

Random small blocks twinkling on the screen and progressively gets worse is usually a bad video card. Monitors can have bummed pixels and they are usually in a stuck state for the JUNCTION. Looking at a black background and seeing a white pixel or pixels that never change states is usually a sign of a display having issues. A couple bad pixels is not a problem but a whole bunch is. I bought a new Toshiba netbook in 2009 that had a single TINY pixel that was always white. Its not noticeable until your background goes black with display on and the back light shines through that pixel location. Problem didnt get worse so I lived with it.Sounds like the resolution is not set to the Native resolution of the Display. (1920x1080 in this case)