Because the network card isn't actively transferring data and the hard drive cannot write data, the download is effectively paused or severed. If you are downloading a file via a browser or a torrent client, the connection will time out, and you will likely have to restart the download or hope the client can resume it once the computer wakes up.
Apple has a feature called . This allows Mac computers to occasionally "wake up" without turning on the screen to perform background tasks like iCloud syncing or downloading system updates. This is usually enabled by default on Macs with Apple Silicon or those plugged into a power source. What About "Hibernate"? when computer is in sleep mode does it still download
Modern Standby blurs the line, but it’s designed for lightweight updates and notifications, not heavy file transfers. If you want to wake up to a finished download, either disable sleep entirely or just turn off the screen manually. Because the network card isn't actively transferring data
Apple computers have a feature called Power Nap . When enabled, your Mac can occasionally wake up from sleep mode (without turning on the screen or fans) to perform background tasks. This includes checking for email, performing Time Machine backups, and sometimes continuing software updates or App Store downloads. However, standard web browser downloads (like a PDF from a website) generally do not continue. This allows Mac computers to occasionally "wake up"