Your internet isn’t the problem — Windows is throttling your wired connection

I leaned toward a wired connection to solve my internet issues, so it was frustrating when my Ethernet connection began stuttering during calls and games. This was particularly painful because speed tests returned normal results.

After thorough troubleshooting, I found that the same energy-saving features designed to make Ethernet greener were creating an unpleasant experience in practice — it’s time to check if they affect you, too.

Ethernet adapter latency issues

A wired connection can still feel slow

When you run a speed test, it measures how much data can be transferred within a set window between the internet and your device. It doesn’t test for delays even before the webpage starts loading, quick freezes you can experience mid-call, or stutter during active gameplay. All these are latency problems that Ethernet may experience, even when you have impeccable speed test results.

A very likely cause is Energy-Efficient Ethernet, or Green Ethernet, depending on the adapter. The feature, which is part of the IEEE 802.3az standard, helps reduce the adapter’s power draw when it isn’t processing data. During these moments of no traffic, the adapter enters Low Power Idle (LPI), a low-power state. When new data arrives, the adapter must return to full power. On certain adapters or drivers—and sometimes on the switches or routers at the other end—the wake-up can be slow enough to notice.

Whether you’ll notice it comes down to three things working together. The chipset itself sets a floor: some silicon exits Low Power Idle in microseconds, other silicon takes longer, and that’s baked into the hardware. The driver adds another variable, since it’s the one negotiating that wake-up with whatever’s on the other end of the cable — an older or poorly optimized driver can tack on a delay the hardware alone wouldn’t have. And the link partner matters too: if the switch or router port you’re plugged into is itself slow to come back from its own low-power state, the wake-up takes longer, no matter how fast your adapter is.

That’s why the same feature can sit there unnoticed on one machine and cause a very noticeable stutter on another — it’s not a single setting misbehaving, it’s several components that all have to wake up quickly for the pause to stay invisible.

The Windows settings worth checking

Two power-saving options can make a wired connection feel less responsive

You can find both settings in the same place. Open Device Manager (right-click the Start menu and select Device Manager), expand the Network adapters category, and double-click your Ethernet adapter to open its properties.

Navigate to the Power Management tab and uncheck the option “Allow the computer to turn off this device to save power.” This option is enabled on many devices plugged into power. With it enabled, Windows will power down the Ethernet adapter when it is idle.

Next, navigate to the Advanced tab and look for Energy Efficient Ethernet or Green Ethernet in the Property list. Set this property to Disabled. Restart the computer after making both changes.

Even though the power-saving difference may not be that significant, these features are better suited for a laptop running on battery power. Here, even tiny power savings extend runtime. With a desktop plugged into power, they don’t offer much of an advantage.

One more setting can limit your connection

Auto Negotiation helps your adapter use the fastest supported link

Speed & Duplex is a second feature within the Advanced tab’s Properties list that you should explore. This feature has a real impact on how your adapter and your router or switch agree on a link speed. Set it to Auto Negotiation. This way, both ends of the connection can communicate and always use the highest speed and duplex mode supported by both devices.

If Speed & Duplex is forced to a fixed value, say 100 Mbps Full Duplex, your connection will be locked to that number, whether it’s a gigabit adapter or not. Forcing it to a fixed value was once a common troubleshooting step, so if you inherit a PC or have reused an old configuration file, this can be the setting you’re currently running.

Regardless of the settings you see on your adapter, you can verify the link speed in Task Manager’s Performance window, which always shows your actual link speed. You should also consider installing the latest driver from the adapter or PC manufacturer if the problem persists. Other properties in the list, such as Flow Control, RSS, and Large Send Offload, are best left at their defaults. I may change them only if there’s a specific, already-diagnosed driver bug I’m chasing.

Simple checks confirm whether Windows is throttling the connection

Rather than doing a speed test, go back to any activity that made you notice the stutter. This may require loading the same websites, joining a call, or downloading. If everything works fine, then these settings have fixed your problem.

Set reasonable expectations: these changes won’t increase your internet speed; they address inconsistency and latency. But if it persists, look at other troubleshooting tips, check for cable damage, confirm the router/switch port isn’t limited to a lower speed, and inspect for failing ports. It may also be an ISP-related problem.