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user_t8981o
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10/07/2026 7:26 PM

My Netgear CM3000 upload speed capped at 40 Mbps.

My Netgear CM3000 diagnostics show that the upstream OFDMA channel is successfully Locked at 36.2 MHz (Power: 43.3 dBmV), proving my modem hardware is fine. However, my upload speeds are still capped at 40 Mbps. This confirms my modem is stuck on a partial or legacy bootfile. Please have a Tier 2 network engineer review my account provisioning codes and force-push the correct Next-Gen / Mid-Split speed tier configuration file to my modem's MAC address.

Multiple techs visited my home and they couldn't fix the issue. field technician verified my physical line is capable of high upload speeds, but my speeds are capped at 40 Mbps. Also, multiple front-line agents couldn't solve it either. 

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user_t8981o

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7 hours ago

@Xfinity Support can you help here?

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EG

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7 hours ago

Concern moved here to the Customer Service help section for greater exposure to Comcast corporate employees (The Digital Care Team) for assistance.

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XfinityOrlandoM

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7 hours ago

@user_t8981o

Please be mindful that sending unsolicited Direct Messages to an Official Employee of the Xfinity Community Forum is a violation of Forum Guidelines. In the future we ask that you please find the most appropriate public board for your question type and post it there. If needed, we may invite you to send us a Direct Message.

 

Thanks for reaching out to us we apologize for any inconvenience as the Neatgear CM3000 does list as a compatible modem for our next generation speeds so you should be getting at least 100 megabytes to upload.

 

Since we already have you in the direct messaging platform, I sent you a message and I look forward to hearing from you

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user_t8981o

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Issue Resolution Summary: Netgear CM3000 Upload Speed Cap (Fixed)

The Problem:
Despite having a physical line verified by a technician to support high-speed uploads, my Netgear CM3000 was locked at ~40 Mbps upload speed.

Initial Misdiagnosis by Support:
Frontline support repeatedly misdiagnosed the issue, incorrectly blaming customer-owned hardware and claiming the modem was at fault. Specifically, support agents noted that the MAC address was incorrectly reporting and provisioning in Xfinity's database as a legacy CM500-100NAS (an obsolete DOCSIS 3.0 device that does not support mid-split/high-split tiers or OFDMA bonding).

The Root Cause:
The backend system was mismatched. Even though the Netgear CM3000 hardware was successfully locking onto the upstream OFDMA channel (confirmed via modem diagnostics at 36.2 MHz), the account was tied to an obsolete device profile and legacy bootfile.

The Solution:
After correcting support's misdiagnosis and insisting on an escalation, the backend engineering team corrected the device provisioning profile to properly recognize the Netgear CM3000, updated the bootfile, and pushed the correct Next-Gen speed tier configuration.

Following a final modem power cycle, full multi-gigabit upload speeds are now unlocked and operating as expected. Leaving this here in case others run into the frontline "modem fault" script when it's actually a backend provisioning/MAC profile mismatch!

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