Slow Upload speeds fast download speeds

Hello @user_le4ptc, and thank you for taking time out of your day to reach out to our Xfinity Community Forums. 

As someone that works from home myself, I definitely understand how important it is to have my internet services working correctly at all times and would feel the same way in your shoes. Other than restarting your router, have you done any other troubleshooting? If not check out this list posted by one of our experts: https://forums.xfinity.com/conversations/your-home-network/internet-troubleshooting-tips/602dae4ac5375f08cde52ea0

Let me know if this helps.

I had the same problem (gigabit plan with very fast download but super-slow upload). I desperately needed to get it fixed because it was not only causing my Zoom calls to burp and chirp the video but even destroying my app demos for prospective clients because of the slow uploads. I finally gave up on my calls with tech support because their advice (modem refresh, switch ports, reinstall drivers, etc.). I decided to give AI a shot. Since I use Windows and am fully in a Microsoft 365 environment, I described the problem to Copilot and it quickly narrowed down the possibilities to about 5 very specific system settings to try. Here's the ones that finally and permanently fixed the problem for me.

Go to Device Manager/Network Adapters. Right-click your Gigabit controller. Select Properties. Click on the Advanced tab. Scroll down the left table and select Large Send Offload (there are 2 of them, so do both one at a time) and select Disable. Click OK for both. Re-boot. That's it.

Good luck!