10Gbps internet connection isn't maxing out 2.5Gbps network card? (upvote.au)

submitted 1 year ago* (last edited 1 year ago) by dan@upvote.au to c/networking@sh.itjust.works

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I have a 10Gbps internet connection. On a system with a 10Gbps Ethernet card, I can get ~8Gbps down and ~6Gbps up:

I'd expect this to easily max out a 2.5Gbps network connection. However, while the upload is maxed (or close to it), I can only ever get ~1.0 to 1.5Gbps down:

Both tests were performed on the same system. The only difference is that the first one uses a TRENDnet 10Gbps PCIe network card (which uses an Aquantia AQC107 chipset) whereas the second one uses the onboard NIC on my motherboard (Intel I225-V chipset).

This is consistent across two devices that have 10Gbps ports and two devices that have 2.5Gbps ports.

I'm using an AdTran 622v ONT provided by my internet provider, a TP-Link ER8411 router, and a MikroTik CRS312-4C+8XG-RM switch. I'm using CAT6 cabling, except for the connection between the router and the switch which uses an SFP+ DAC cable.

I haven't been able to figure it out. The 'slower' speeds are still great, I just don't understand why it can't achieve more than 1.5Gbps down over a 2.5Gbps network connection.

Any ideas?

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[-] seedbedUnmoved@lemm.ee 4 points 1 year ago* (last edited 1 year ago)

Can you test without the MikroTik? I've been having similar issues with my Mikrotik set up (I had a half a dozen or so posts on reddit about it). It appears the devices are not handling flow control correctly and the buffers are being overwhelmed. I'd test first without the Mikrotik and then experiment with flow control on the port. Be aware that you seem to have to disable and reenable the interface for flow control to take effect (or reboot). It has been getting better with more recent versions of RouterOS but it is still not "right" it used to be much much slower.

Edit: fixed a typo

[-] Lunchbox05@lemm.ee 3 points 1 year ago

Something to keep in mind when testing upload and download speeds is your drive and memory read/write speed. Your true throughput is not just a test of NIC and network but also the rest of your PC

[-] dan@upvote.au 1 points 1 year ago

The PC can definitely handle it since both tests were done on the same PC, just a different NIC.

Ookla's speed test doesn't write to or read from disk, so disk performance doesn't impact it :)

[-] Lunchbox05@lemm.ee 1 points 1 year ago

Cool, if you ruled that out then last thing I would do is run Wireshark during both tests and see how they compare

[-] Scend@feddit.de 3 points 1 year ago

I don’t have that chip myself, but it looks like it could be at least similar to (this issue)[https://www.intel.com/content/www/us/en/support/articles/000057261/ethernet-products/gigabit-ethernet-controllers-up-to-2-5gbe.html], since your speed seems suspiciously close to half of the chipset’s max. Do your versions already match these fixes?

[-] dan@upvote.au 1 points 1 year ago

Thanks. This sounds related. Unfortunately I can't find the firmware (NVM) update it mentions. I have an "ASUS ROG STRIX B550-F Gaming (WI-FI)" motherboard, and the latest Intel LAN driver on their site (V1.1.4.38) does not have the firmware image in the download, nor does the install.bat update it (it just removes old drivers then installs the new driver).

Based on this thread, it sounds like this chipset has known issues: https://www.techpowerup.com/forums/threads/is-the-intel-i225-v-ethernet-chip-still-a-buggy-piece-of.303335/page-2