When something moves faster than our eyes can refresh we see a motion blur [...] So I guess a monitor with a refresh that high would look like a construct game with 1 million times motion blur :P
I don't know what Construct does for "motion blur", but if it's in any way realistic, then the higher the frame rate the less motion blur you get. Or rather, the less motion blur you need: motion blur is an artefact of filming at low frame rates, and recreating it in a game lets you get away with a lower frame rate without looking stuttery.
Motion blur comes doesn't come from the eyes but from a camera. At a normal movie framerate of 24 fps, each film frame can be exposed for up to 1/24 second. This means that a fast-moving object will produce not just one image of itself, but overlapping images in all the places it goes through during that 1/24 second. This makes the image of the moving object blurred.
Now shoot the same thing with a high speed camera that takes 500 frames per second (or, for a single frame, grab any still image camera and set the exposure timing to 1/500 second). Each frame can only be exposed for a much shorter time, so the same moving object will produce much less blur per frame: each frame shows the object moving through a far shorter distance. At 1/500 second you're unlikely to see any blurring, unless you're taking pictures of Superman going faster than a tall building.
The "refresh rate" of human perception is not really a fixed number, but any monitor refresh frequency over 60 Hz or so is fairly pointless because the brain will tune out anything more than that.