The pixels don't physically exist.
In theory you could allow creating and writing to a 1400x1200 frame buffer (or 20,000 x 20,000) but then you would still have to scale it down and display it using only the physical 1024x768 pixels, causing smearing / blurring.
Hit print screen, go into Paint, paste an image of your desktop, go to Image > Stretch/Skew, and type in 75% / 75%. That's what you'd get.