A: 4K â also known as UHD (more on this in the next answer!) â is a picture technology that quadruples the number of pixels found in a full HD picture. These pixels are usually arranged in a 3,840 x 2,160 configuration, compared with the 1920x1080 you get in a full HD TV.
Files with the .7z extension are very similar to Zip files. These files are compressed archive files, usually created by the 7-Zip file archive utility. 7Z files can make it easier to send files and folders over email and the Web.
Some files such as image and pdf files do not compress much at all. As for the types of compression available in 7-zip, I tested a txt file with each type. The top 4 compression formats, starting from the smallest, are .xz, .7z, .gz, and .zip.