Question Speed test discrepancies and how to push the issue with an ISP

[ShotgunDiplom4t]

Hey all,
Apologies if I'm posting this in the wrong place.
Not long ago I upgraded to a 1 Gbps line through Centurylink. The price is good, but thus far I'm not really getting what I'm paying for. After several appointments with their technicians they remedied an issue on their end, and I discovered that my Ethernet NIC was switching from 1 Gbps to 100 Mbps. Both of the issues have been taken care of, and I've definitely seen an improvement in my speed, but I'm still not getting anywhere near the 1 Gbps that I'm paying for. I've run several speed tests in safe mode (as the ISP technicians do the same) and only one of them shows results anywhere near what I'm supposed to be getting. Not surprisingly, it's the speed test the technicians use.
I'm hardwired in using a STP CAT6 cable, and my NIC is compatible with the speeds I'm trying to get.
I've attached screenshots of the tests that were done in safe mode. Does anyone have any advice/ideas if there's something on my end that would be causing these discrepancies? Am I completely ignorant in terms of how these things work?
I'm at a loss for how to pursue this with the ISP. At this point they just keep saying they're going to send technicians out, and the technicians just run their speed test and say it's good.

Below is my speed test from Ookla when I'm not in safe mode, but not gaming or doing anything else. If I'm playing a game on the internet, it drops to around 200mbps. Given that I'm seeing such discrepancies, I can't tell what I'm actually getting and when.

 

[peptobismal]

Ummm... the last speed test seems about right. On Google Fiber I get about 940 down and up. I am assuming you have some issues if you can get those speeds in safe mode but not without.

You should NEVER be using that much bandwidth for gaming... at gig speeds you are actually going to get between 900-970, I have never seen the full 1000, haha. But you are talking 700 Mbps for gaming? Or even 366 Mbps based on your last screenshot... there is no game that requires that much speed at all, ever. I'd be willing to bet on it, unless you are playing and running the game server on your same network.

I would stick with Ookla's results more so than anyone else's they seem to be the most accurate and I would get crazy "low" speeds on other tests, which could be because their servers just weren't capable of getting to my gigabit speeds.

Do you have a router attached and is it set to CTF?

Also, have you used Speedguide.net's TCPOptimizer and seen if this remedies it?

Also, have you upgraded your NIC driver lately?
Turn off everything in your in your Ethernet Properties under "This connection uses.." except Internet Protocol 4. Click OK.
Then go back in and make sure that the following are disabled:

1. Auto Disable Gigabit
2. Energy-Efficient Ethernet
3. Flow Control
4. Green Ethernet
5. Interrupt Moderation
6. Jumbo Frame
7. Large Send Offload IPv4 & IPv6
8. Power Saving Mode
9. Receive Side Scaling
10. TCP Checksum Offload IPv4 & IPv6

Then make sure these are set as so:

1. Transmit Buffers is set to MAX
2. Receive Buffers is set to MAX value
3. Speed & Duplex is Auto Negotiate

These would potentially be your main culprits the other could be LargeSystemCache, ECN Capability, RSC, and Windows Scaling Heuristics (which is defaulted to Disabled).

If you can get 900+ Mbps on Ookla in any scenario and then for some reason can't... it has to be something is not configured right. The key is just figuring out where... because if you are getting those speeds in safe mode then chances are that you have something running that is taking a lot of bandwidth that you are missing.

If everything above does not help... go check out BlackViper's Windows 10 (or 7 depending on what you are using) Service Configuration list and set all of them as safe. Try W10Privacy or Spybot's Anti-Beacon. And if all else fails run a very thorough Virus scan, I usually use Malwarebytes and then SuperAntiSpyware to be on the safe side.

 

[ShotgunDiplom4t]

Hello,

Thank you for the detailed response.
I see my speed come in anywhere between 250 to 600, sometimes when I'm doing nothing at all but browsing the internet.
Regarding my router, I just have the regular router provided to me by my ISP. It's a Zyxel C3000z, if that makes any difference. Not sure if it's set to CTF as I'm unfamiliar with that but I'm going to check.

I haven't upgraded my NIC recently, but I went through the properties and disabled the options you recommended. I couldn't find options for green Ethernet, energy efficient Ethernet or jumbo frame (I did find and disable jumbo packet though, if that's the came idea.) I also adjusted the transmit and receive buffers to max.
I didn't see any improvements through doing that, however.

I'll look into SpeedGuide's TCP optimizer.
I don't really know anything about LargeSystemCache, ECN Capability, RSC, and Windows Scaling Heuristics, or how to address the issues possibly presented by them, but I'll start looking into that.
And as far as virus scanners go, I have malwarebytes periodically scan my system but I'll check into the other scanner you mentioned.

 

[peptobismal]

Yeah you might not have them I was going off my Realtek NIC settings, and those were the maximum throughput with best latency settings I ended up with after hours of research. So, that was mainly just to see if it was on your side.

https://www.centurylink.com/asset/home/help/downloads/internet/c3000z-datasheet.pdf

Is this the device you have? Because I see no where that it says it is capable of Gigabit speeds at all... on the Wireless yeah, but the actual Internet speeds it's capable of do not show that it could even get up there? I might be mistaken, but I am assuming you originally had a much slower speed and then later on decided to upgrade and they didn't mention or acknowledge that you would probably need a new modem?

It has a VDSL2 35B profile which if you read up on that is only capable of about 300 Mbps down and 100 Mbps up.
https://en.wikipedia.org/wiki/VDSL

So show them that .PDF file, that clearly states "VDSL2 (G.993.2) Bonding - 200Mbps/100Mbps* down/up data rates " on the second page. They might try to convince you that the Gigabit Ethernet ports for WAN and LAN mean that it is capable of those speeds, but that wouldn't be true at all... most everything has a gigabit Ethernet port if it's from the past 10 years, but it doesn't mean the hardware is capable of pushing those speeds at all.

You may have to be very firm with them... even a little colorful with language to get any kind of results, because they will do whatever they can to convince you you are wrong and they are right. You are their customer and they should know their own devices capabilities... especially when they have the datasheet on their website that states it's not a Gigabit capable modem, if it was it would be prominently displayed as a main selling point.

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