Most 4K TVs on the market today come equipped with advanced upscaling technology that can enhance lower resolution content in real time, making it look great on the high-resolution display of the TV. This is achieved by adding additional pixels of information into the image to improve its clarity and sharpness.
While the upscaled content won't be as sharp as native 4K content, most 4K TVs are able to make regular HD content look a bit better thanks to the process of upconverting or upscaling. Upscaling technology is particularly important when watching content with a lower resolution than the native resolution of your TV, such as DVDs, cable TV channels, or even Blu-ray movies. This is because the TV needs to scale the image to fit the full area of the screen.
When it comes to watching lower resolution content on a 4K TV, the upscaling capabilities of the TV can make a big difference in the overall picture quality. It's worth noting, however, that upscaling is not a special feature reserved only for 4K TVs, as all modern TVs have a specific number of pixels and upscale images to fit the screen. So, while a 4K TV may offer some benefits in terms of picture quality when watching lower resolution content, it's not necessary to buy a 4K TV specifically for its upscaling capabilities.