Gigabit fiber gotten significantly slower

Internet access discussion, including Fusion, IP Broadband, and Gigabit Fiber!
8 posts Page 1 of 1
by joyjit » Sat Aug 31, 2019 10:37 am

Got Sonic Gigabit Fiber (I am in San Francisco, Mission) installed in 2018 Feb.

Was great for a long time (see my old post here: viewtopic.php?f=10&t=5359&p=35989 )

Was getting approx 900Mbps up/down

But recently it has become much slower. I have started measuring it and for (at least) the last few weeks I am getting around 250Mbps up/down

I don't know when the slowness started, I only started measuring it again around a couple of weeks ago.
(I am using speed test utility)

Nothing in my setup has changed:
1. I have the same CAT6 wiring I had earlier
2. Same Win 10 PC connected to ethernet to ASUS router
3. Same ASUS router as before

Question to Sonic -- has something changed on their side?

by joeyyung911 » Sat Aug 31, 2019 11:19 am
Restart router and/or ONT.
by Larns576 » Sat Aug 31, 2019 1:06 pm
Try different speed test sites such as or

If you are using, make sure to download their windows app instead of running the test via their web site.
by joyjit » Sat Aug 31, 2019 4:35 pm
"Restart router and/or ONT. "

Sorry, I had forgotten to clearly say, but yes, that was the first thing I had tried. Did not help.
by joeyyung911 » Sat Aug 31, 2019 7:25 pm
What speed do you get if a computer is directly connected to the ONT?
by joyjit » Sun Sep 01, 2019 4:02 pm
"What speed do you get if a computer is directly connected to the ONT?"

Tried it just now

Directly connected to ONT: 400 Mbps Down / 500 Mbps Up

Connected via Ethernet via ASUS Router: 288 Mbps Down / 266 Mbps Up.

There seems to be two problems:
- Even directly with ONT I am no longer getting 1 Gbps. Need Sonic's help in diagnosing this one.
- The router is additionally contributing to the slowness. I will follow up on this one (perhaps the new firmware on the router is buggy...)
by joyjit » Sun Sep 01, 2019 4:46 pm
After going through every single one of the ASUS RT-68U settings, I discovered that the "NAT Acceleration" setting, even though it said "Auto", was actually turned off.

I know from memory that this used to be enabled before. So some recent Firmware update must have screwed it up.

Setting it to Disabled, and then back to Auto has had a huge improvement on bandwidth.

I just did another speedtest and I got 660 Down/950 Up!
by Sonic Guest » Mon Sep 02, 2019 9:50 pm
Sonic's fiber infrastructure is GPON. This means you don't get dedicated bandwidth to your premises. The total bandwidth per fiber is typically split between 32 households where total bandwidth is 2.5 Gbps down/1.2 Gbps up. I don't know what Sonic's split topology is. Because a household is not constantly transferring data, this system works in practice by using TDMA (divide bandwidth to households by time). So when you have multiple people performing these speedtests, you might not "see" the full bandwidth. Sonic's fiber has best effort SLA and that is typical for a consumer product. ... r-networks

Don't get too hung up on these speed upstream/downstream tests. If you expect to see 900 Mbps up/downstream 24x7 you've bought the wrong product. Such performance costs hundreds or thousands of dollars per month for guaranteed bandwidth. A much better benefit of fiber is network latency. Going from 24 milliseconds or more down to 2-3 offers a better experience.

Let's say you do see 900 Mbps up/down. It may not stay that way as more people subscribe in your area. The thing about fiber though is it's much more cost-effective and easy to upgrade the infrastructure than a cable (hybrid fiber-coaxial) network.

If Sonic is a responsible ISP and upgrades their infrastructure as needed your performance should not drop significantly. I've been a Sonic subscriber for over a decade, starting from 3 Mbps, 6 Mbps DSL, to FTTN for myself, 3 Mbps DSL to Sonic Fiber for my parents. They have made many upgrades to their services and as long as Dane continues to be CEO, I feel they will continue doing what's best for their network and customers.
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