I have a powerful computer with gigabit internet over Ethernet, but Steam downloads for about two seconds, stop for roughly five seconds, and then resume. The disk-usage graph looks like a mountain range, and downloads that should take around 10 minutes can stretch into many hours. I've already tried the usual troubleshooting steps without any improvement. What could be causing this stuttering?
3 Answers
Try adding the Steam library folder to your antivirus real-time scanning exclusions, since some antivirus programs inspect every chunk as it’s written. Clearing Steam’s download cache and switching to a nearby download region are also worth trying. If the drive is healthy, watch CPU, disk active time, and network usage in Task Manager while downloading to see which resource hits its limit.
This pattern often means Steam is alternating between downloading and processing the data. Steam has to decrypt, unpack, and write each chunk to the drive, so a slow or unhealthy drive can make the network pause until the disk catches up. Check which drive your Steam library is installed on, run a SMART health check, and look for bad sectors or other warnings. If it’s an older hard drive, that may be the bottleneck.
It could also be a connection problem between your network and the download server. Packet loss or repeated retransmissions can make TCP slow down dramatically even when your normal speed tests look fine. A packet-loss test or a capture with Wireshark can help identify that, and a bufferbloat test may reveal whether the connection struggles under load.

Related Questions
Lenovo Thinkpad Stuck In Update Loop Install FilterDriverU2_Reload