A black pixel of your text, will result in a double black pixel now. You will see that it is bigger, but the relation between height and width is respected, and basically, nothing is wrong. And your border of 10 pixels, will be displayed as a border of 20 pixels now. So your textbox of maybe 500 by 150 pixels, will be converted into a textbox of 1000 by 300 pixels.
So PowerPoint will double each size automatically. The presentation setup is 50% of your final output dimensions. Imagine you have a textbox on a slide with text in black, on a white background and a rectangle around it. PowerPoint will reduce the output size when the presentation design is larger than the output size. When you run a smaller PowerPoint slideshow on a larger television or computer screen, then PowerPoint will always enlarge the presentation so that it will fit on your screen. And this is not ideal when using PowerPoint for digital signage. Default PowerPoint presentations are not in HD they are of lower quality. You see already a problem with default PowerPoint presentations. So we know that the default dimension of a presentation is 1280 x 720, and that your HD television is capable of displaying 1920 x 1080.
