Flint 2 – Only getting 500 Mbps over PPPoE instead of 1 Gbps

Technical Support for Routers
1

Hi everyone,

Today I replaced my ISP-provided router with a media converter from my provider, and connected it directly to my GL.iNet Flint 2 (MT6000). I'm using PPPoE and configured it using the credentials received via SMS from my ISP.

The connection works, but I'm only getting around 500 Mbps download and upload, even though I have a 1 Gbps symmetric fiber connection.

Here’s what I’ve tested and confirmed:

  • PPPoE is connected and stable
  • Connected via LAN cable (Cat 6)
  • My computer has a 1 Gbps NIC, and is showing proper link speed
  • Port status on the router confirms 1 Gbps link
  • Tried multiple DNS servers (Cloudflare, Google, ISP default)
  • No VPN or bandwidth throttling enabled
  • Speed tests performed using speedtest.net and fast.com

Before switching to the Flint 2, I used my ISP’s router and could consistently get full 1 Gbps speeds.

Could this be related to some additional PPPoE-related configuration on the Flint 2? (e.g., MTU size, NAT acceleration, offloading options, SQM, etc.)

I’ve attached screenshots of my current setu

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Any help or tips would be appreciated!

2

Is the network acceleration enabled? Try both the hardware and software acceleration.

Also try a PPPoE MTU of 1492.

1 Like
3

Thanks for the suggestion!

I tested both Hardware Acceleration and Software Acceleration modes (under Network Acceleration settings), and I also manually set the PPPoE MTU to 1492 as recommended.

Unfortunately, the result is still the same — speedtest shows around 500 Mbps up and down, no matter which acceleration mode I use.

Any other ideas what could be limiting the throughput?

4

@BogusPL

I know a similar problem from before. Check your network cable and make sure you have Cat 6 network cable.

5

Yes, I'm already using Cat 6 cables – nothing has changed in terms of wiring. The same setup was working just fine with my previous ISP-provided router, where I could consistently reach full 1 Gbps speeds.

So I don’t think the cable is the issue in this case.

6

Someone on here had an issue that you described, they used a new cable and it worked, went back to the old cable and it went slower again even though the cable worked fine with the other router.

I don’t know why but try it anyway.

7

The Flint 2 should be able to achieve 1100 Mbit download and 900Mbit upload via PPPoE with the hardware acceleration enabled.

Which firmware version do you use?

Is there a noticeable speed difference between 4.7.x, 4.6.8 and 4.5.8?

Note: Always do NOT keep the settings when doing a downgrade, because downgrading can cause problems when the config is from a higher version.

Is hardware and software offloading also enabled according to LuCi/Advanced settings?

Mb2FWdN
Mb2FWdN1096×777 28.9 KB

8

the media converter should give it a check.

9

I’ve just replaced all LAN cables with brand new Cat 6 cables, and unfortunately — the issue persists.
The only cable I haven’t replaced yet is the fiber patchcord between the media converter and the wall socket.
Also, I noticed something odd:
Even though I enabled both hardware and software acceleration in LuCI, after rebooting the router, those settings reset back to disabled. Not sure why that’s happening.
For reference, I’m running firmware version 4.7.4.
Media conventer - LXT-01G-D

10

Run Htop to see CPU usage

11

Are you using QoS or any other additional "features"? Sometimes these features are not compatible with hardware or software acceleration and the router will turn the feature off automatically.