Ethernet is supposed to be the fast, reliable option.

So it can be confusing when your Windows 11 laptop achieves:

650 Mbps over Wi-Fi

but only:

94 Mbps over Ethernet.

Before blaming Windows, your broadband provider or the network card, check one number:

Ethernet link speed.

If Windows says the Ethernet connection is running at 100 Mbps, no amount of DNS tweaking, browser resetting or speed-test repetition is going to turn it into a 1 Gbps connection.

The computer and the network have negotiated a 100 Mbps link.

And that gives us somewhere useful to start.

First: Check Your Ethernet Link Speed

Go to:

Settings > Network & internet > Ethernet

Open the active Ethernet connection and look for:

Link speed (Receive/Transmit)

You might see:

• 100/100 Mbps
• 1000/1000 Mbps
• 2500/2500 Mbps
• 5000/5000 Mbps

Alternatively, open PowerShell and run:

Get-NetAdapter

Microsoft's Get-NetAdapter command returns the basic properties of Windows network adapters.

This number immediately changes the investigation.

Windows reports 100 Mbps

Investigate:

cable → port → dock/adapter → auto-negotiation → driver

Windows reports 1.0 Gbps or faster

The physical Ethernet link is probably not your 100 Mbps bottleneck.

Investigate:

internet connection → router/firewall → VPN/security software → driver → traffic → test methodology

This distinction can save a huge amount of wasted troubleshooting.

Why 94 Mbps Is Such an Important Clue

If your speed test repeatedly produces roughly:

90–95 Mbps

on a network that should provide hundreds of megabits per second, check the negotiated Ethernet speed immediately.

A nominal 100 Mbps Ethernet connection cannot deliver the entire theoretical 100 Mbps as application payload because network protocols introduce overhead.

So results around the low-to-mid 90 Mbps range are characteristic of a 100 Mbps link.

That means the broadband connection may be perfectly healthy.

Your Ethernet connection itself may simply have negotiated at the wrong speed.

Step 1: Replace the Cable

Start with the cheapest and easiest component.

Microsoft recommends checking the physical Ethernet connection and trying another cable early in its Windows Ethernet troubleshooting guidance.

Use a known-good:

• Cat5e
• Cat6
• Cat6a

cable.

For ordinary Gigabit Ethernet, you do not need an exotic expensive cable.

A correctly made Cat5e cable is capable of Gigabit Ethernet.

What matters is whether all the required conductors and pairs are working properly.

Why a Damaged Cable Can Still “Work”

This catches people out.

A damaged Ethernet cable doesn't necessarily produce:

No network connection.

Instead, the devices may successfully establish a connection at:

100 Mbps

rather than:

1 Gbps.

So somebody sees:

Connected

and assumes the cable must be fine.

It isn't necessarily.

Intel specifically identifies the cable as one of the main things to investigate when an adapter remains limited to 100 Mbps despite Auto Negotiation being configured correctly.

Replace the cable before doing anything complicated.

Step 2: Try Another Network Port

Move the cable to another switch or router port.

Then check the link speed again.

If it changes from:

100 Mbps

to:

1.0 Gbps

you have narrowed the problem significantly.

The original port may have:

• physical damage
• incorrect configuration
• negotiation problems
• a 100 Mbps limitation

On managed business switches, also check whether somebody has manually configured the port.

Step 3: Don't Forget the Wall Socket and Patch Panel

In an office, the cable between the PC and wall socket is only part of the connection.

The actual path may be:

PC → patch lead → wall socket → structured cabling → patch panel → patch lead → switch

A fault anywhere in that chain can affect link speed.

This produces a very useful test.

Connect the computer directly to the switch using a known-good short cable.

If it negotiates:

1 Gbps

directly at the switch but:

100 Mbps

from the desk socket, Windows probably isn't your problem.

Investigate the structured cabling.

Step 4: Leave Speed & Duplex on Auto Negotiation

Open:

Device Manager > Network adapters

Double-click the Ethernet adapter.

Choose:

Advanced

Find:

Speed & Duplex

For a normal modern network, this should usually be:

Auto Negotiation

Intel explicitly recommends Auto Negotiation for Gigabit Ethernet.

Don't automatically force:

1.0 Gbps Full Duplex

because somebody on a forum told you to.

Gigabit Ethernet normally relies on auto-negotiation.

If the cable, switch and adapter are healthy, they should negotiate the appropriate link.

What Is Duplex?

Full duplex means the connection can transmit and receive simultaneously.

Half duplex restricts that behaviour and can cause severe performance problems in modern networks.

Modern switched Ethernet should normally operate full duplex.

But that doesn't mean manually selecting Full Duplex is the correct fix.

Auto Negotiation normally handles it for you.

Step 5: Check the Hardware's Actual Capability

Make sure every component supports the speed you expect.

Check the:

• PC network adapter
• switch
• router
• USB Ethernet adapter
• docking station

A laptop connected to a 100 Mbps Ethernet adapter will never achieve 1 Gbps simply because your broadband service is 1 Gbps.

Likewise, a:

2.5 GbE PC

connected to a:

1 GbE switch

will normally negotiate at 1 Gbps.

The link operates at the highest mutually supported speed the equipment and connection can establish.

Step 6: Check USB Ethernet Adapters

Many thin laptops no longer have built-in Ethernet.

Instead they use:

• USB Ethernet adapters
• USB-C adapters
• docking stations

That introduces another potential bottleneck.

Check whether the adapter actually supports:

1 Gbps

or:

2.5 Gbps

rather than assuming it does.

Also check how it connects to the PC.

A high-speed Ethernet adapter connected through an unsuitable USB port, cable or hub can be limited by the USB connection itself.

For testing:

connect the adapter directly to the laptop.

Avoid the hub.

Retest.

Step 7: Test Without the Dock

Business laptops frequently connect Ethernet through USB-C or Thunderbolt docks.

If that's your configuration, remove the dock from the equation.

Where possible, test using:

• built-in Ethernet
• a known-good direct USB-C Ethernet adapter
• another dock

If Ethernet becomes fast without the dock, investigate:

• dock firmware
• dock Ethernet driver
• USB-C cable
• Thunderbolt/USB4 drivers
• dock hardware

Don't reinstall Windows because a £100 docking station has a problem.

Step 8: Update the Correct Ethernet Driver

Open:

Device Manager > Network adapters

Identify the actual Ethernet controller.

Then obtain the appropriate driver from:

• PC manufacturer
• dock manufacturer
• network-adapter manufacturer

Microsoft also recommends updating or reinstalling the Ethernet network-adapter driver when troubleshooting wired network problems.

For business laptops, I would normally start with the manufacturer's approved driver.

Dell, HP and Lenovo, for example, may validate drivers against:

• firmware
• docks
• power management
• enterprise hardware configurations

The newest generic driver isn't automatically the best driver for every business laptop.

Step 9: If the Problem Started After an Update, Consider the Driver

If Ethernet worked perfectly yesterday and became slow immediately after:

• Windows Update
• driver update
• dock firmware update
• BIOS update

don't ignore the timing.

Open:

Device Manager > Network adapters > Ethernet adapter > Properties > Driver

If:

Roll Back Driver

is available and the evidence points towards the driver change, rolling back can be a useful test.

But don't permanently run an outdated vulnerable driver merely because it performs better.

If rollback fixes the problem, check for a newer corrected release.

Step 10: Temporarily Test Energy-Efficient Ethernet

Some Ethernet adapters include settings such as:

• Energy Efficient Ethernet
• Green Ethernet
• Power Saving Ethernet
• Advanced EEE

These reduce power consumption.

Occasionally a particular combination of:

adapter + driver + switch

can behave badly.

As a diagnostic test, temporarily disable the relevant energy-saving option in the adapter's Advanced properties.

Restart and retest.

If nothing changes, put it back.

Avoid changing 15 advanced adapter settings simultaneously.

Otherwise, if performance improves, you won't know which change fixed it.

Windows Reports 1 Gbps, but Ethernet Is Still Slow

Now the investigation changes.

Suppose Windows reports:

1.0 Gbps

but your internet speed test only reaches:

250 Mbps

while Wi-Fi achieves:

700 Mbps.

The cable is clearly capable of establishing a Gigabit link.

So stop treating this as a 100 Mbps negotiation problem.

Investigate throughput instead.

Test Without Wi-Fi

Temporarily disconnect Wi-Fi while testing Ethernet.

This removes ambiguity about which network path Windows is using.

Then run several tests.

Don't rely on one result.

Compare:

• internet speed
• local network transfer
• latency
• another computer

The distinction between internet speed and LAN speed is extremely useful.

Test a Local File Transfer

Suppose:

Internet over Ethernet = 200 Mbps

but:

local server transfer = 900 Mbps

Your Ethernet connection clearly isn't limited to 200 Mbps.

The bottleneck lies elsewhere.

Possibilities include:

• ISP
• router
• firewall
• VPN
• security inspection
• remote test server

Conversely:

Internet = 200 Mbps

and:

LAN = 200 Mbps

makes the local Ethernet path much more suspicious.

Check VPN and Security Software

Business PCs may route traffic through:

• VPN clients
• secure web gateways
• endpoint security
• content inspection
• cloud proxies

Temporarily testing without an appropriate VPN can help identify whether it is the bottleneck.

But don't disable business security controls permanently just to improve a speed-test number.

If security inspection genuinely limits throughput, investigate the configuration or capacity of the security service.

Check Adapter Statistics

Advanced troubleshooting should look beyond raw speed tests.

PowerShell can show useful adapter information:

Get-NetAdapter

Microsoft documents that Get-NetAdapter can also expose more detailed adapter properties and driver information.

On managed switches, look for:

• CRC errors
• input errors
• dropped packets
• link flapping
• speed changes

A connection negotiating at 1 Gbps but accumulating large numbers of physical errors can still perform terribly.

That's another reason link speed alone isn't the entire story.

Don't Start by Changing DNS

DNS affects how names such as:

hgmssp.com

are translated into IP addresses.

It does not normally explain why a large file downloads at:

90 Mbps instead of 600 Mbps.

Changing DNS may improve lookup responsiveness in some circumstances.

It won't turn a 100 Mbps Ethernet link into Gigabit Ethernet.

Check the physical link first.

Don't Disable IPv6 as a Generic Speed Fix

The internet is full of guides recommending:

Disable IPv6.

Don't use that as routine Ethernet troubleshooting.

IPv6 is a normal part of modern Windows networking.

Disabling it without evidence can create other problems while doing nothing about the actual cable, switch, driver or adapter fault.

Don't Start With Network Reset Either

Windows 11 provides:

Settings > Network & internet > Advanced network settings > Network reset

Microsoft describes Network Reset as a last step after other network troubleshooting has failed. It removes installed network adapters and reinstalls them with default settings after reboot.

That means it can also affect:

• VPN clients
• virtual adapters
• Hyper-V networking
• custom network configuration

Network Reset can be useful.

It shouldn't be your first response to a cable negotiating at 100 Mbps.

The 5-Minute Diagnostic

If Ethernet is slower than Wi-Fi, I would initially do only this:

1. Check Ethernet link speed.
2. If it says 100 Mbps, replace the cable.
3. Try another switch/router port.
4. Bypass the wall socket or dock where possible.
5. Confirm Speed & Duplex = Auto Negotiation.
6. Update the correct Ethernet/dock driver.
7. If link speed is already 1 Gbps+, stop chasing the cable as a 100 Mbps problem and investigate actual throughput.

That short sequence will diagnose a large percentage of Ethernet performance problems.

A Useful Example

Suppose a business has:

900 Mbps broadband

A desktop achieves:

93 Mbps Ethernet

A laptop achieves:

650 Mbps Wi-Fi

Windows reports:

100/100 Mbps Ethernet link speed

You replace the Ethernet cable.

Windows now reports:

1000/1000 Mbps

The speed test reaches:

850 Mbps

Problem solved.

You did not need to:

• reinstall Windows
• reset TCP/IP
• change DNS
• disable IPv6
• modify the Registry
• replace the PC

You followed the evidence.

What If Several PCs Are Slow?

This is particularly important for businesses.

If one PC negotiates at 100 Mbps, investigate:

that PC, cable and port.

If 25 computers suddenly become slow, investigate what they share:

• switch
• firewall
• router
• VLAN
• internet connection
• configuration change
• driver deployment
• dock model
• Windows update

Twenty-five PCs rarely develop unrelated Ethernet cable faults simultaneously.

Look for the common dependency.

When Ethernet Being Slower Than Wi-Fi Is Actually Normal

There is one final misconception worth correcting.

Ethernet is not automatically faster than Wi-Fi in every configuration.

Imagine:

Ethernet: 1 Gbps

Wi-Fi 7: capable of more than 1 Gbps under favourable conditions

In that environment, a modern wireless client could genuinely achieve greater raw throughput than a Gigabit Ethernet port.

That does not mean Ethernet is broken.

Ethernet may still offer:

• lower latency
• lower jitter
• greater consistency
• less interference
• more predictable performance

So the correct question isn't:

“Is Wi-Fi faster than Ethernet?”

It is:

“Is this Ethernet connection performing at the speed its hardware and network design should support?”

How Hamilton Group Can Help

Hamilton Group helps businesses diagnose network performance properly rather than simply replacing hardware until something improves.

We can help with:

• Ethernet performance problems
• business Wi-Fi
• switches and VLANs
• structured cabling
• firewalls
• routers
• broadband
• Windows 11 networking
• network drivers
• USB-C and Thunderbolt docks
• network monitoring
• managed IT support

If one PC is stuck at 100 Mbps, the problem may be a £5 patch cable.

If an entire office is slow, the cause may sit further upstream.

The important thing is finding the actual bottleneck.

Visit or call 0330 043 0069 to discuss business network and IT support.