A:Answer Hi PaddyMac. That resolution of 1600 x 900 is has an Aspect Ratio of 16:9 or 1.78:1 which is a TV resolution. Your 1080p TV has a resolution of 1920 x 1080 which is also an Aspect Ratio of 16:9 or 1.78:1. The LG UHD 70 Series 60 inch 4K HDR Smart LED TV, Model # 60UN7000PUB has a resolution of 3840 x 2160 which is also an Aspect Ration of 16:9 or 1.78:1, so when the 4K Upscaler in the TV upscales the lower resolution, just as with your 1080p TV, it will also upscale 1600 x 900 cleanly to fill the screen. TV broadcasts aslo have an Aspect Ratio of 16:9 which is why the 16:9 Aspect Ratio is called the TV Aspect Ratio...^IFV