Laptop Ethernet and Wifi Speed Gated by Router; Not Modem. Other Devices at Full Speed.

[kgladst]

SOLVED Dell utility "SmartByte Network Services" at fault. Killed and removed it and all speeds are back to what I'd expect.



Problem:
I recently got a new modem from Spectrum to allow speeds over 100Mbps as my plan increased to 200Mbps. However, my laptop's speed wired to the router and on wifi caps at about 7 Mbps. But wired directly to the modem gets me the 90 Mbps I'd expect on the laptop's 100 Mbps adapter so I don't think the adapter is bunk. This is a new problem (as best I can tell) since the modem was added to my setup.

Setup
Nothing fancy - no network sharing, just me in the apartment typically running only one device at a time. Have never dabbled with custom settings on the router, everything is set on DHCP/Default settings, as are the various devices.

Modem: Arris TM1602 (Pure modem, no router functions that I can access)
to
Tenda AC15 Router (Firmware v15.03.05.18_multi)
to
(Wired) Desktop - No issues. Speeds measure at 150 Mbps+
(Wired) Smart TV - No issues.
(Wifi) Tablet - No issues. Speeds at 70 Mbps+
(Wifi) Phone - No issues. Speeds at 70 Mbps+
(Wired/Wifi) Problem laptop - Speed caps at 7 Mbps

Specs on laptop:
Dell Inspiron 5559, Windows 10 Home v1803
Adapters:
Intel Dual Band Wireless AC 3160 - Driver up to date at v18.33.13.4
Realtek PCIe FE Family Controller - Driver up to date at v10.28.615.2018

Solutions tried and other info:

• 
  - Connected with a different cat5 cable and a different port on router
  - Soft reset on modem and router
  - Factory default reset on router
  - Related driver updates
  - No bandwidth limits are placed on the laptop or any other device by the router
  - Comparison of adapter settings between desktop and laptop looks identical (to my knowledge)
  - A variety of command line resets (netsh winsock reset, etc)
  - Windows 10 network reset command
  - No issues reported on Windows 10 network troubleshooter
  - First line Spectrum tech support gave an "it could be our problem but it probably isn't" response. Ha.

I'm stumped. I've run out of Google-fu. I don't think it's hardware as the laptop performs correctly plugged into the modem and everything else works correctly on the router. I've been scratching my head over why both the wired and wifi would cap at the same speed. If feels like there's some deep setting interfering between the router and laptop but I only know enough to know that I don't know. I'd love to get some more in-depth solution ideas or possibly some network diagnostic tools a novice could hopefully get more info from. Hoping I don't need to resort to wiping the laptop.

Thanks, and let me know if there's any more info I can provide.

 

[Ralston18]

Do you have both wired and wireless adapters enabled on the laptop?

Only one or the other should be enabled and configured for use on your network.

 

[kgladst]

Do you have both wired and wireless adapters enabled on the laptop?

Only one or the other should be enabled and configured for use on your network.

Just tried ethernet connected, wifi adapter disabled and vice versa - no change, stuck at 7 Mbps. Here's a weird one though, I switched from the 2.4 Ghz band to 5 Ghz mid speed test and got a positive result of 90 Mbps. If I retest though I'm back to 7.

 

[Ralston18]

Any chance of a duplicate IP address on your network?

Have you set any devices to a static IP that may end up being duplicated when the laptop is powered on?

 

[kgladst]

Any chance of a duplicate IP address on your network?

Have you set any devices to a static IP that may end up being duplicated when the laptop is powered on?

Doesn't look like it. All devices are set to DHCP and no LAN IPs are currently shared.

 

[BuddhaSkoota]

Just tried ethernet connected, wifi adapter disabled and vice versa - no change, stuck at 7 Mbps. Here's a weird one though, I switched from the 2.4 Ghz band to 5 Ghz mid speed test and got a positive result of 90 Mbps. If I retest though I'm back to 7.

When you are testing, are you disabling the unused adapter to be certain the laptop is using only the one under test?

If it's common to both wired and wired connections, it could be that some running application is using bandwidth. I would suggest using the Task Manager / Resource monitor to find if there is network activity from some other app.

 

[kgladst]

Just tried ethernet connected, wifi adapter disabled and vice versa - no change, stuck at 7 Mbps. Here's a weird one though, I switched from the 2.4 Ghz band to 5 Ghz mid speed test and got a positive result of 90 Mbps. If I retest though I'm back to 7.

When you are testing, are you disabling the unused adapter to be certain the laptop is using only the one under test?

If it's common to both wired and wired connections, it could be that some running application is using bandwidth. I would suggest using the Task Manager / Resource monitor to find if there is network activity from some other app.

Yep, disabled. I assume you mean to keep an eye out for anything odd in the right Network column in Task Manager, nothing fancier than that?

 

[kgladst]

I seem to have found my solution in disabling SmartByte Network Service. Seems to be something Dell put into an update in July.

I appreciate your help, Ralston and Buddha!