u/artrflr

(Note: I worked through this troubleshooting with Claude and had it help draft this write-up from my notes — wanted to be upfront about that.)

Sharing this in case it saves someone else a support call. Had degraded speeds on a Fios 1 Gig plan for a while — noticeable both over Wi-Fi and wired ethernet — and the root cause turned out to be something a full factory reset wasn't even necessary to fix.

Setup: CR1000A router, Fios 1 Gig plan. Speeds had felt slow generally, on both Wi-Fi and any wired devices, for some time before I isolated it. Bought a Cat 6 cable and a USB-C-to-ethernet adapter specifically to rule out Wi-Fi as a factor and test wired throughput directly.

What I found, step by step:

1. First wired test (plugged into a standard LAN port on the router): ~83 Mbps down/up. Low, but I initially chased the wrong lead — turned out iCloud Private Relay was on and routing the test through a relay server three states away, adding latency and skewing the number.
2. Turned off Private Relay, retested on the same port: ~90 Mbps down/up. Confirmed the link itself was negotiating full Gigabit (checked in OS network settings — 1000baseT full duplex), so it wasn't a cable/adapter/link-speed issue. Just a flat ~90 Mbps ceiling on a connection that should do 900+ — matching what I'd also been seeing on Wi-Fi.
3. Plugged the same cable/adapter directly into the ONT instead of the router (bypassing it entirely): ~924 Mbps down, ~850 Mbps up. Same cable, same computer, same test server. That ruled out the ISP/provisioning side completely — the fiber line itself was delivering full speed. The router was the bottleneck, for both wired and Wi-Fi clients.
4. Looked into a known CR1000A firmware bug where the 10Gb LAN port specifically caps upload speed — but I'd tested on a standard Gigabit port, not the 10Gb one, so that didn't match (also that bug reportedly only affects upload; mine was capped symmetrically on both directions).
5. Was about to do a full factory reset. As prep, I just moved the WAN cable from the ONT back into the router (no reset button pressed, no reboot) — and retested: ~908 Mbps down, ~818 Mbps up wired, and Wi-Fi came back up to a healthy ~727 Mbps down/~189 Mbps up. Both fixed just from cycling the physical WAN link.

Takeaway: the router wasn't hard-capped at 90 Mbps — it had drifted into some kind of degraded state that throttled throughput across the board (wired and wireless both), and simply disconnecting/reconnecting the WAN cable cleared it. No factory reset needed. I'd also had intermittent connection drops for a few weeks before this that a router-only reboot (not the ONT) would temporarily fix — in hindsight I think it's the same underlying issue, just showing up as a speed cap instead of a full drop this time.

If you're seeing degraded speeds — wired or Wi-Fi — on a CR1000A:

• Rule out Private Relay / VPN on your test device first.
• Check your OS network settings to confirm the ethernet link actually negotiated Gigabit (not just plugged in).
• If you have access to the ONT, testing directly into it (temporarily swap the router's WAN cable for your laptop) is the cleanest way to isolate router vs. ISP.
• Before a full factory reset, try just unplugging/replugging the WAN cable between the ONT and router. Cheap thing to try, and it fixed it for me — both wired and Wi-Fi.

Still monitoring in case it recurs — will update if a factory reset ends up necessary down the line.