9800 or the monitor? random blurring

[SSibalNom]

I'm running a 9800p bba and a hp p1120 monitor. the problem i had is , every once in a while, the screen kind of flickers once, then becomes very blurry... when i turn it off then turn it on, everything is back to normal. the thing is this happened with the first p1120 i got (both are refurbs)... the samsung 955DF i took back before that was 2mm smaller on one side of the screen, and i returned 2 A90F's because it seemed like the OSD settings wouldnt display. When i see this kind of thing i immediately think tis the monitor... but having had it happened to so many, im thinking its the video card... is this possible? could it be giving it bad signals? or is there anything else i could check out? i have all my warranty stuff and could RMA it if this is the prob, any help would be greatly appreciated, thanks