Is PageSpeed's Testing Network Setting Outdated? Significant Discrepancy with Real Users' Mobile LCP Data

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#16,487 opened on May 13, 2025 0 comments 0 reactions 0 assignees View on GitHub

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Description

![Image](https://github.com/user-attachments/assets/868e5fa6-f5b2-43c6-b423-e72dae4716aa)

![Image](https://github.com/user-attachments/assets/050b3a59-217f-48f6-bb15-d39d154cbdd1)

![Image](https://github.com/user-attachments/assets/b8a79c3a-7f6e-4f66-a471-5ca3d7249eb3)

On mobile devices, the discrepancy between the LCP (Largest Contentful Paint) data of real users and the real-time field test data from PageSpeed is quite significant, which is quite confusing.
I've noticed that the network settings used in PageSpeed real-time testing have remained unchanged for a long time: "150 ms TCP RTT (Round-Trip Time), 1,638.4 kb/s throughput (Simulated)." Does this setting no longer reflect the network conditions experienced by the majority of real users today?

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Is PageSpeed's Testing Network Setting Outdated? Significant Discrepancy with Real Users' Mobile LCP Data

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