At around 11 am PST today, Steam's total bandwidth usage more than doubled to 23.5 Tbps thanks to the surprise release of Halo Infinite's free-to-play multiplayer. The sudden spike wasn't just a line on a graph: When I started the download, Steam could only deliver around 78 KB/s over my high-speed fiber connection. The Steam client estimated that it would take me three days to download Halo Infinite's 23.7 GB multiplayer package at that rate.
Others at PC Gamer were likewise stuck downloading Halo Infinite through a cocktail straw, and a number of fans on Twitter have lamented the slow download. I also saw someone who happened to be downloading a different game on Steam at the time complain, like a poor shopper who'd been shoved into a 2003 GameStop midnight release line while looking for a used copy of Luigi's Mansion.
But Steam hasn't fallen over yet. If you're struggling to download Halo Infinite on Steam, try pausing and restarting the download.
When I restarted the download, Steam hit its normal rate and Halo Infinite made it to my SSD in a few minutes. When I tried to download a different game after that, it went back to a trickle of bytes. Pausing and restarting a few more times once again fixed it. (You can also try getting Halo Infinite through the Microsoft Store, of course.)
23.5 Tbps is a big spike on Steam, but not abnormal for a launch. On September 28, the day New World launched, Steam's global bandwidth usage peaked at 24.1 Tbps (if this page archive is correct). New World's download size is 14GB bigger than Halo Infinite multiplayer, so each person would've spent longer downloading it.
Steam's bandwidth usage is trending back down to normal levels now, according to Valve's reporting page.
At the time of writing, Halo Infinite has 139,461 concurrent players on Steam, putting it just below New World for active players. (Update: It peaked at 272,586.)
Relatedly, we recently reminisced about the worst internet connections we've ever had, and at least we aren't in the 56kb/s days. (Though I probably still have a pile of AOL floppy disks somewhere.)