How to Fix Slow WiFi Upload Speed on Windows PC: Drivers, Settings, and Hardware Fixes

Slow upload speed on a Windows PC is one of the most frustrating WiFi problems because it’s so one-sided — your phone uploads fine, your laptop uploads fine, but your desktop or another Windows machine crawls. The root cause is almost always software: a bad driver, a misconfigured network adapter setting, or a Windows power policy that throttles the radio to save energy. This guide walks through every fix in order from quickest to most involved.

Step 1: Confirm the Problem Is Your PC, Not Your Network

Before changing anything, run a speed test at wifispeed.com on both your Windows PC and another device (phone, tablet) connected to the same WiFi network at the same time. If the other device uploads at full speed and your PC does not, the problem is Windows-side. If both devices are slow, the issue is your router or ISP — see our guide on fixing slow upload speed for network-level solutions.

Also note whether the slow upload happens on WiFi only or on Ethernet too. If Ethernet is fine and WiFi is slow, the WiFi adapter driver or its settings are the likely culprit.

Fix 1: Update Your WiFi Adapter Driver

An outdated or corrupt WiFi driver is the single most common cause of asymmetric slow upload speed on Windows PCs. Manufacturers release driver updates specifically to fix throughput bugs, and the driver bundled with Windows Update is often months behind the manufacturer’s current release.

1. Press Windows + X and select Device Manager.
2. Expand Network adapters and find your WiFi adapter (e.g., “Intel Wi-Fi 6E AX210” or “Realtek RTL8852BE”).
3. Right-click it and choose Update driver › Search automatically for drivers.
4. If Windows finds nothing, visit the adapter manufacturer’s website directly. For Intel adapters, use the Intel Driver & Support Assistant. For Realtek, download from Realtek’s site or your motherboard manufacturer’s support page.
5. Install, reboot, and re-test upload speed.

Important: Always download drivers from the hardware manufacturer or your PC/motherboard OEM — not from third-party driver update tools, which can install incorrect or outdated versions.

Fix 2: Disable Large Send Offload (LSO)

Large Send Offload is a Windows networking feature that offloads TCP packet segmentation to the network adapter. In theory it improves throughput; in practice it frequently causes upload speed to tank on WiFi adapters due to firmware bugs.

1. Open Device Manager, right-click your WiFi adapter, and select Properties.
2. Click the Advanced tab.
3. Find Large Send Offload V2 (IPv4) and set the value to Disabled.
4. Find Large Send Offload V2 (IPv6) and also set it to Disabled.
5. Click OK, reboot, and test again.

Fix 3: Adjust Power Management — Stop Windows Turning Off the Adapter

By default, Windows allows itself to power down the WiFi adapter to save energy. When it ramps back up after an idle period, upload throughput can stay throttled for minutes at a time.

Disable adapter power-off

1. In Device Manager, right-click your WiFi adapter and select Properties.
2. Click the Power Management tab.
3. Uncheck Allow the computer to turn off this device to save power.
4. Click OK.

Set Wireless Adapter to Maximum Performance

1. Open Control Panel › Power Options and click Change plan settings on your active plan.
2. Click Change advanced power settings.
3. Expand Wireless Adapter Settings › Power Saving Mode.
4. Set both “On battery” and “Plugged in” to Maximum Performance.
5. Click OK and retest.

Fix 4: Force the Adapter to Use 5 GHz (or 6 GHz)

If your adapter is connecting on the 2.4 GHz band instead of 5 GHz, your upload speed will be a fraction of what it could be. You can force the preference in the adapter’s advanced settings.

1. In Device Manager, open your WiFi adapter’s Properties › Advanced tab.
2. Look for a property called Preferred Band, Roam Aggressiveness, or Band Preference.
3. Set it to Prefer 5 GHz band (or 6 GHz if you have a WiFi 6E/7 adapter and router).
4. Also look for 802.11 mode or Wireless Mode and ensure it is set to Auto or the highest mode your router supports.

For more on band differences, see our 2.4 GHz vs 5 GHz vs 6 GHz guide.

Fix 5: Disable the Killer Prioritization Engine (Dell & Intel Systems)

Many Dell laptops and desktops with Intel Killer WiFi adapters ship with the Killer Intelligence Center software. Its “Killer Prioritization Engine” feature classifies and re-prioritizes network traffic — and is a well-documented cause of severely throttled upload speeds on Windows 10 and 11.

1. Open Killer Intelligence Center from the Start menu.
2. Navigate to Settings.
3. Toggle Killer Prioritization Engine to Off.
4. Retest upload speed. Many users report upload jumping from under 5 Mbps back to full speed immediately.

If you don’t use the Killer software’s features, consider uninstalling it entirely via Settings › Apps and using the standard Intel WiFi driver instead.

Fix 6: Flush DNS and Reset TCP/IP Stack

A corrupted TCP/IP stack or stale DNS cache can cause erratic upload performance even when the adapter hardware is healthy. This reset takes under a minute and is worth doing before more invasive changes.

Open Command Prompt as Administrator and run these commands in order:

netsh winsock reset
netsh int ip reset
ipconfig /release
ipconfig /flushdns
ipconfig /renew

Reboot after running all five commands, then retest.

Fix 7: Ensure WLAN Autoconfig Service Is Running

The WLAN Autoconfig service manages WiFi connections in Windows. If it’s set to Manual or Disabled, your adapter may operate in a degraded state that caps throughput.

1. Press Windows + R, type services.msc, and press Enter.
2. Find WLAN AutoConfig in the list.
3. Double-click it. Set Startup type to Automatic and click Start if it’s not already running.
4. Click OK and retest.

Fix 8: Replace or Upgrade the WiFi Adapter

If all software fixes fail and your PC has an old WiFi 5 (802.11ac) or WiFi 4 (802.11n) adapter, the hardware itself may be the bottleneck. A PCIe WiFi card upgrade is inexpensive and straightforward for desktops. Look for cards based on the Intel Wi-Fi 6E AX210 or Intel BE200 (WiFi 7) chipsets — both have mature, well-maintained drivers and reliable upload performance. For laptops, a USB WiFi 6 adapter (like the TP-Link Archer TX20U) can bypass a problem internal adapter entirely.

Before purchasing, confirm your router supports WiFi 6 or newer. See our best WiFi routers of 2026 if you need to upgrade both ends of the link.

Quick Diagnostic Checklist

1. Run a speed test — confirm other devices upload at full speed
2. Update WiFi adapter driver from the manufacturer’s website
3. Disable Large Send Offload V2 (IPv4 and IPv6)
4. Set power plan to Maximum Performance and disable adapter power-off
5. Force 5 GHz band preference in adapter Advanced settings
6. Disable Killer Prioritization Engine if present
7. Reset TCP/IP stack and flush DNS
8. Confirm WLAN Autoconfig service is Automatic and running
9. Consider a PCIe WiFi 6E or WiFi 7 card if hardware is old

Work through the list top to bottom and retest after each step — most users fix the problem by step 3 or 4. If upload speed is still slow after all of these changes, run a speed test via Ethernet to rule out a router or ISP issue, then check our bufferbloat guide to see if queued packets are artificially capping your measured upload.