No, Windows does not combine LAN and WLAN speeds to increase total throughput. The operating system uses a single active route for outbound traffic based on interface metrics, meaning you get the speed of the fastest single connection, not the sum of both. To optimize your specific setup with a 1Gbit/s ISP line, an old 100Mbit/s cable, and a Wi-Fi adapter, you must manually configure which interface handles general internet traffic and which handles local transfers.
Understanding Network Metrics and Routing
Windows manages network interfaces through a routing table that assigns a "metric" value to each connection. The lower the metric, the higher the priority. By default, Ethernet usually has a lower metric than Wi-Fi because it is considered more stable and reliable. However, this is a configuration setting, not a hardware limitation. When you attempt to use both simultaneously for a single download or stream, Windows selects only one path. It does not load-balance across multiple gateways for standard HTTP or HTTPS traffic without specialized third-party software or complex policy-based routing configurations that are beyond typical home user scope.
If your goal is to maximize speed, you should ensure that the high-speed 1Gbit/s connection is prioritized. If your old Ethernet cable is limiting you to 100Mbit/s, it might actually be dragging down your perceived performance if Windows tries to use it as the primary gateway while the Wi-Fi offers 200-300Mbit/s. You need to explicitly tell Windows to prefer the faster link for internet access.
Adjusting Interface Metric Values
You can change which interface Windows prefers by modifying the automatic metric. Open the Network Connections panel (press Win + R, type ncpa.cpl). Right-click your preferred adapter (likely the Wi-Fi or the Gigabit Ethernet if available) and select Properties. Select Internet Protocol Version 4 (TCP/IPv4) and click Properties. Click the Advanced button. Uncheck Automatic metric and enter a lower number, such as 10, for the interface you want to prioritize. Set the other interface to a higher number, like 20. This forces Windows to send internet traffic through the selected adapter.
Optimizing Your Specific Hardware Setup
Your scenario involves three distinct components: a 1Gbit/s ISP connection, an old 100Mbit/s Ethernet cable, and a Wi-Fi adapter rated at 200-300Mbit/s. The bottleneck here is clearly the old Ethernet cable. If you plug that cable into your router and set it as the primary connection, you will cap your wired speed at 100Mbit/s regardless of your ISP plan. Meanwhile, your Wi-Fi might offer better real-world throughput depending on signal strength and interference.
To get the best speed, you should physically replace the old Ethernet cable with a Cat5e or Cat6 cable capable of Gigabit speeds. If replacement is not immediately possible, configure Windows to use the Wi-Fi adapter as the primary internet source by lowering its metric, as described above. This allows you to utilize the full potential of your wireless connection while keeping the slow Ethernet port available for local network tasks where high bandwidth is not critical.
For users who frequently share their internet connection from one adapter to another, understanding how to manage these paths is crucial. You can learn more about managing connection sharing in our guide on How to Share Your Windows Internet Connection via Ethernet Port for WiFi Router Connection Sharing. This ensures that even if you reconfigure your primary adapter, secondary devices remain connected correctly.
Local Network Traffic vs. Internet Traffic
While you cannot combine speeds for internet downloads, you can optimize local traffic. If you have a NAS or another PC on the same network, traffic between them stays within your local subnet. In this case, the interface used depends on the IP address of the destination. If your NAS is connected via the slow 100Mbit/s Ethernet, local transfers will be limited to that speed. If it is connected via Wi-Fi, transfers will be limited by wireless speeds. There is no benefit to having both adapters active for local file transfers unless you are using a distributed storage solution that spans multiple interfaces, which is rare for home setups.
Ensure that your router’s DHCP server is assigning addresses correctly so that local traffic does not get routed out to the internet and back, which would waste bandwidth. Check your routing table by opening Command Prompt and running route print. Look for the 0.0.0.0 network entry, which represents all internet traffic. Verify that the Gateway listed there corresponds to your fastest interface.
Why Load Balancing Is Not Built-In
Some users expect Windows to act like a bond, combining 100Mbit/s and 300Mbit/s for a theoretical 400Mbit/s pipe. This is not supported natively because TCP connections are tied to a single source IP and interface. Splitting a single download across two IPs causes packet ordering issues that most servers and clients cannot handle. While some advanced routers support Multi-WAN load balancing, the PC itself simply picks the best route. Therefore, the strategy must focus on selecting the single best path rather than combining them.
Frequently Asked Questions
Can I use software to bond my LAN and WLAN?
Native Windows networking does not support link aggregation or bonding for standard internet connections. Third-party tools exist but often require administrative privileges and can introduce instability. For most users, optimizing the metric of the best single adapter is the most reliable solution.
Will disabling Wi-Fi improve my Ethernet speed?
Disabling Wi-Fi will not increase the speed of your Ethernet connection if the bottleneck is the physical cable or the router port. However, it may reduce CPU overhead and radio interference, potentially stabilizing the connection. It does not bypass the 100Mbit/s limit of an old Cat5 cable.
How do I check if my Ethernet cable is Gigabit capable?
Right-click your network icon in the taskbar and open Network & Internet settings. Click on Change adapter options. Double-click your Ethernet adapter. Look at the Speed field. If it says 100.0 Mbps, your cable or router port is limiting the connection. If it says 1.0 Gbps, the cable is capable of Gigabit speeds.
What is the difference between LAN and WLAN in Windows?
Lan refers to Local Area Network connections, typically Ethernet cables. WLAN refers to Wireless Local Area Network, or Wi-Fi. Windows treats them as separate interfaces with independent drivers and metrics. They operate independently unless configured for specific bridging or sharing scenarios.
Does using both adapters drain more battery on laptops?
Yes, keeping both Wi-Fi and Ethernet radios active consumes more power than using just one. If you are on battery power, consider disabling the unused adapter in Device Manager to extend battery life. This also reduces heat generation inside the laptop chassis.