Fast Ethernet and slow Wi-Fi point toward radio, client or placement conditions, not automatically a slow ISP plan.
Before you change anything
This is a diagnostic entry point. The source supports the general check, not a confirmed root cause for your device.
What to check first
Does the same client improve near the main router?
Record the exact model, hardware revision, firmware and recent change before adjusting settings. If you cannot answer the question, keep the cause open.
Narrow the likely path
| Observation | Next check |
|---|---|
| Wired path is also slow | Check WAN service, link negotiation and upstream equipment. |
| Only Wi-Fi is slow | Compare near-router radio performance with the problem room and mesh backhaul. |
| Latency rises under load | Measure upload/download load separately before changing QoS or SQM. |
Decision after the first test
Use the same test server near the router and at the weak spot. Check whether the client attached to a distant mesh node.
Use a documented next step
Verify before escalating
After each change, repeat the exact failed task. If the result is unchanged, restore the previous setting and use the official support link for your exact hardware revision. Don’t assume a menu or capability from a related model.
Official sources
- TP-Link slow wired/wireless diagnostic separation (full_text; checked 2026-11-01)
Check your exact US model, hardware revision, and firmware on the linked support page before changing settings.