This time, we will show you how to optimize your Windows 11 network to improve wired LAN communication speeds.
If you use the default settings of Windows 11, your internet speed may be reduced in some environments and may not reach its maximum speed.
The methods introduced on this page are those that I have tested and found to be effective.
Optimizing your Windows 11 network settings may improve the following: Please read the notes carefully before configuring the settings.
- Improved web page loading speed
- Increased file download speed
- Improved file upload speed
- Reducing lag in online games
How to optimize your network settings in Windows 11 and what to watch out for
Network and Internet Settings
1. Change DNS Server
By default, the DNS server address of your ISP is automatically assigned.
A DNS server is responsible for translating domain names into IP addresses.
To explain it simply,
- Let's say you want to visit the website "google.com (domain name)" and access it.
- Your computer then asks the DNS server, "What is the address for google.com?"
- The DNS server tells you, "The address of google.com is 172.217.161.206 (IP address)."
- Your computer will use that address to display the google.com website.
There is no problem with using your provider's DNS server, but depending on the provider, the speed at which domain names are converted to IP addresses may be slow.
If your provider's processing speed is slow, it will take a long time for your domain name to be converted into an IP address, which will result in your website displaying slowly.
Therefore, we recommend switching to a faster DNS server.
By changing to a faster DNS server, the time it takes for a domain name to be converted into an IP address may be reduced, which may result in faster website display.
The author recommends the world-famous free public DNS server "Cloud flare Public DNS."
To change your DNS server to "Cloud flare Public DNS",
1.Task tray (notification area)Right-click the network icon and click "Network and Internet Settings."
2. "Network and Internet" will open, so click "Properties".
3. Click "Edit" to the right of "DNS Server Assignment."
4. "Edit DNS Settings" will appear, so click "Automatic (DHCP)" and select "Manual".
5. Both "IPv4" and "IPv6" are set to "Off", so please change them to "On".
6. Each item will then be displayed and you will be able to enter it. Enter the address of the "Preferred DNS Server" in "Preferred DNS" and the "Alternate DNS Server" in "Alternate DNS".
| Cloud flare Public DNS | Preferred DNS Server | Alternate DNS Server |
| IPv4 addresses | 1.1.1.1 | 1.0.0.1 |
| IPv6 addresses | 2606: 4700: 4700 :: 1111 | 2606: 4700: 4700 :: 1001 |
7. Once you have entered both "IPv4" and "IPv6", click "Save".
Then you will see the changes reflected as shown in the image below.
*The DNS server changes have already been reflected, so there is no need to restart your computer.
2. Disable unnecessary components
By default, the network adapter has some components enabled that are not required.
It might be easier to understand if you say, "There are unnecessary parts attached."
Having unnecessary components enabled will result in extra network traffic (the amount of data passing through the network in a given period of time).
By avoiding this, the network will not become congested and data will flow more smoothly.
To put it simply, the less traffic there is, the smoother cars can drive, right? It's the same idea.
To disable unnecessary components,
1.Task tray (notification area)Right-click the network icon and click "Network and Internet Settings."
2. "Network and Internet" will open, so click "Advanced network settings".
3.Click on the name of the network adapter you are currently using.
4. Click "Edit" to the right of "Other adapter options."
5.The network adapter properties will then be displayed, so uncheck any unnecessary components.
Generally, only four components are required:
- Client for Microsoft Networks
- File and Printer Sharing for Microsoft Networks
- Internet Protocol Version 4 (TCP/IPv4)
- Internet Protocol Version 6 (TCP/IPv6)
6. Once you have unchecked all the components you do not need, click OK.
Depending on your environment, some disabled components may be necessary. Click on each item to see the explanation below, so please read it carefully.
For normal use, you won't need any other components than the four listed above, but if you experience any problems after disabling them, revert them.
Network driver settings
*Make sure you install the latest version of the network driver.
Receive and transmit buffers
The receive and transmit buffers are set to low values by default, but you can maximize network performance by setting these values higher.
Receive/RX Buffers → Affects download speed
- role: It is a "receptacle" that temporarily stores data (downloaded data) coming into your PC from the Internet until it is processed by the CPU.
- Influence:
- If the size is small: When a large amount of data arrives at high speed, the receiver becomes overwhelmed and packets (data) are dropped (packet loss). The lost data must be resent, resulting inSlow download speeds international success.
- If you increase the size: This prevents overflow and allows stable data reception, especially on high-speed lines.Increased download speedYou can expect better performance and stability (however, this will consume more memory on your PC).
Transmit/TX Buffers → Affects upload speed
- role: This is a "waiting area" where data to be sent from a PC to the Internet (upload data) is temporarily queued until it is actually sent.
- Influence:
- If the size is small: Even if an application tries to send data, the "waiting room" is full and the data cannot be delivered immediately, which makes it more likely that the data will be sent while waiting.Slow upload speedsThere is likely to be.
- If you increase the size: Because it can accept a large amount of data as "waiting to be sent" at once, it can send data efficiently.Increased upload speedCan be expected.
For Windows 11, if you have 16GB or more of memory, it should be fine to set the receive and transmit buffers to 4GB (4096) or more.
If your PC has a small amount of physical memory, setting the value too high may cause the system to become unstable.
Windows 11 consumes a lot of memory even when you are not doing anything in particular. Therefore, if your physical memory capacity is 8GB or less, we recommend that you leave it at the default setting.
How to check the amount of physical memory
Task managerYou can check this by opening the "Windows 10" and selecting "Memory" on the "Performance" tab.
The maximum value of the receive buffer that can be set varies depending on the network adapter.Not more than 1/4 of the physical memory capacityTry setting it with
Side effects of setting receive and send buffer values too high
Increasing the receive/transmit buffers of the network adapter may improve throughput (transfer speed), but"Latency (response speed)" worsensThis can cause web pages and online games to appear slower to respond.
This phenomenon is technically known as "Bufferbloat."
Why do web pages load slowly?
The reason is that the nature of the communication required for web browsing and file downloading is different.
- File download (throughput focused):
- This involves pouring in a large amount of data.
- A large buffer allows a large number of packets to be processed at once without dropping any, resulting in faster speeds.
- Web page browsing (latency sensitive):
- When displaying a web page, a large number of small exchanges (round trips) occur, such as "querying DNS," "shaking hands with the server (establishing a connection)," and "retrieving many small files such as images and CSS."
- If the buffer is too large: Too many packets pile up in the buffer (queue), increasing the "waiting time until processing."
- As a result, the time it takes for the button to respond (Ping/RTT) increases, and the perceived "smoothness" is lost.
Analogy: The queue at the cash register
- Small buffer: The queue is short. The staff (CPU) will respond quickly, but when it gets busy, they will turn away customers (packets) (packet loss).
- Large buffer: The queue is extremely long. They don't turn away customers,Customers at the end of the line have to wait a long time to reach the cash register.
Web page loading is sensitive to this "wait time to reach the register," so making the buffer too large can sometimes have the opposite effect.
My environment(Example settings for Marvell AQtion 10Gbit Network Adapter:
Below is an example of the settings in the author's environment (physical memory capacity = 32GB).
1.Start buttonRight-click > Device Manager.
2. Once Device Manager opens, expand the "Network adapters" section, right-click on the name of your network adapter (in my case, Marvell AQtion 10Gbit Network Adapter), and click "Properties."
3. Open the "Advanced Settings" tab, select each item and change the value.
- Receive Buffers = 4096 (maximum)
- Transmit Buffers = 8184 (Maximum)
*2025/11/28: I set them to the maximum value for a long period of time to see what would happen, but if they were too large it would affect the display of web pages, so I currently have both set to "2048".
Setting the MTU Value
What is the MTU value?
The MTU value is the maximum size of data (packet) that can be sent at one time when sending data over the Internet.
In Windows 11, the MTU value is set to 1500 by default and typically does not need to be changed.
However, your provider may limit the MTU value to 1500 or less.
In that case, the default of 1500 is probably too large.
If the MTU value is too large, packets may be split (fragmented) on the network.
Simply put, let's say the MTU value is limited to 1454.
If we compare 1454 to the width of a road (1454cm), data with a width of 1500cm is too large to fit on a 1454cm road.
By dividing this large data into smaller pieces, it becomes possible to send the data smoothly through narrower routes.
The destination then puts the small packets back together, a process known as "fragmentation."
The process of dividing packets and then putting them back together takes some time, so frequent fragmentation can lead to slower communication speeds.
Therefore, you can prevent a decrease in communication speed by telling Windows a clear MTU value to prevent fragmentation from occurring.
How to check and change the MTU value
To check if your MTU value is limited, we recommend the following site:
speedguide.net – SG TCP/IP Analyzer
When you open the page, it will say something like "MTU = 1460", so please check it.
If the MTU value is displayed as "1500", there is no need to change the setting.
If the MTU value is less than 1500, try changing the MTU value using the following steps:
1.Start buttonRight-click and open Terminal (Admin).
2. Type the following command and press Enter:
Get-NetIPInterfaceThis will display a list of network interfaces.
3. What you need to check here is the index number to the left of the name of the network interface (network adapter) you are currently connected to.
"Settings" > "Network and Internet"You can check by opening it.
4. Type the following command and press Enter to change the MTU value:
Set-NetIPInterface -InterfaceIndex インデックス番号 -NlMtuBytes MTU値For example, if you want to set the index number to "12" and the MTU value to "1460",
Set-NetIPInterface -InterfaceIndex 12 -NlMtuBytes 1460.
5. To verify the changed MTU value, enter the following command again and press Enter:
Get-NetIPInterface
The MTU value to the right of the network interface (network adapter) name has changed.
Now that you have finished setting the MTU value, do not close Windows PowerShell and proceed to setting global TCP parameters.
Configuring TCP parameters
Generally, there is no need to change the TCP parameter settings, but after testing it in my environment, the following improvements were observed, as mentioned at the beginning.
- Improved web page loading speed
- Increased file download speed
- Improved file upload speed
- Reducing lag in online games
The default settings for Windows 11 are not optimized for certain environments.
Changing the parameters to suit your environment may dramatically improve your current communication speed.
Configuring Global TCP Parameters
First, check your current settings by typing the following command and pressing Enter:
netsh int tcp show globalThis will display a list of the current global TCP parameters.
Global TCP parameter defaults for Window 11 version 24H2
In my environment, the global TCP parameters for Windows 11 version 24H2 are set as follows by default:
| Name | Status (default for Window 11 version 24H2) |
|---|---|
| Receive-Side Scaling State | enabled |
| Receive Window Auto-Tuning Level | normal |
| Add-on Congestion Control Providers | default |
| ECN Features | disabled |
| RFC 1323 timestamp | enabled |
| Initial RTO | 1000 |
| Receive Segment Coalescing State | enabled |
| Non-SACK RTT Resiliency | disabled |
| Max SYN retransmissions | 4 |
| Fast Open | enabled |
| Fast Open Fallback | enabled |
| HyStart | enabled |
| Proportional Rate Reduction | enabled |
| Pacing Profiles | off |
Details of each global TCP parameter
| Name | Details |
|---|---|
| Receive-Side Scaling State | Receive Side Scaling (RSS): RSS is a network performance optimization technology that allows multiple processor cores to perform parallel processing when receiving network data, improving network throughput. This technology distributes incoming data packets to different processor cores, reducing the burden on a single processor core and improving processing efficiency. It is particularly effective on multi-core processor systems. |
| Receive Window Auto-Tuning Level | Receive Window Autotuning (Autotuninglevel): Autotuninglevel is a TCP protocol setting for automatically adjusting the receive buffer size. The receive window size determines the maximum amount of data that the sender can leave unacknowledged. Automatically adjusting the buffer size can optimize performance, especially in high-latency and high-bandwidth network environments. Depending on network conditions, the system dynamically adjusts the receive window size to improve data transfer efficiency. |
| Add-on Congestion Control Providers | Add-on congestion control providers: Add-on congestion control providers are key to efficiently managing network congestion and improving performance. Choosing the right provider can help you enjoy a better network experience. *In Windows 11, this can be changed using the TCP parameters based on the supplementary template. *Congestion refers to network congestion. |
| ECN Features | Explicit Congestion Notification (ECN): ECN is a network congestion control mechanism that allows network devices (such as routers) to explicitly notify data senders when network congestion occurs, rather than simply dropping packets. This mechanism helps to avoid retransmissions due to packet loss and reduce network latency. ECN helps TCP senders reduce their sending rate and alleviate congestion by passing information in flag bits in the IP header. |
| RFC 1323 timestamp | TCP Timestamp: TCP timestamps are a feature of the TCP protocol used to improve transmission efficiency and delay measurement. By adding a timestamp to each TCP packet, the receiver can measure the packet's round trip time (RTT) and adjust its retransmission timeout (RTO) and sending strategy accordingly. Enabling timestamps can optimize performance when network conditions change. |
| Initial RTO | TCP retransmission control (InitialRTO): InitialRTO is a value used to set the initial retransmission timeout (RTO, retransmission timeout) of the TCP protocol. This value determines the initial waiting time of the TCP retransmission mechanism. If a data packet is not acknowledged within the specified time, the sender will retransmit the data packet. This value is usually set to the default value, which can effectively control the retransmission behavior when packet loss occurs on the network. |
| Receive Segment Coalescing State | Receive Segment Coalescing (RSC): RSC is a network optimization technology used to reduce the number of times a data packet needs to be processed. On the receiving side of the network, when multiple small segments are received, RSC merges these segments into one larger segment, reducing the number of processing and memory accesses and improving network receiving efficiency, especially on high-speed networks. |
| Non-SACK RTT Resiliency | Non-SACK Client RTT Recovery (NonsackRTTResiliency): Non-SACK RTT recovery means that in the TCP protocol, if the client does not support SACK (Selective Acknowledgment), it will use the traditional acknowledgment method to acknowledge data packets and measure RTT (Round Trip Time), in which case the TCP protocol will resume RTT calculation based on the traditional ACK mechanism. |
| Max SYN retransmissions | SYN Retries (MaxSYNRetransmissions): MaxSYNRetransmissions is specified in the TCP protocol. It is the maximum number of times the sender can retry a SYN (synchronize) packet during the connection establishment process. If the receiver does not respond to the SYN packet within the specified time, the sender will retry sending the SYN packet. This value specifies the maximum number of retries to ensure reliable connection establishment. |
| Fast Open | TCP Fast Open (FastOpen): TCP Fast Open (TFO) is an optimization technology that allows clients to send data to servers during the connection establishment process without waiting for the three-way handshake to complete. By shortening the time of the handshake process, TCP Fast Open can reduce connection establishment delays, especially in high-latency networks.The three-way handshake is: When two computers begin communicating over the Internet, they first exchange three "hello" greetings, known as a three-way handshake. First "hello": Computer A tells Computer B, "I want to communicate!" Third "hello": Computer B tells Computer A, "Communication is OK!" Third "hello": Computer A says to Computer B, "Thanks! Let's start communicating!" Only after these three greetings are completed can Computer A and Computer B exchange data. |
| Fast Open Fallback | TCP Fast Open Fallback: FastOpenFallback is a fallback mechanism if the target server does not support TCP Fast Open (TFO). If the target server does not support TFO, the client will fall back to the traditional three-way handshake process. This mechanism ensures that connections are established successfully even in environments that do not support TFO. |
| HyStart | Slow Start Algorithm (HyStart): HyStart is a TCP slow start algorithm that reduces network congestion by more carefully controlling the increase of the congestion window during the slow start phase. While traditional slow start algorithms can result in packet loss, HyStart avoids excessive window increases by predicting changes in network load, optimizing the throughput and stability of TCP connections. * Simply put, an algorithm is a set of steps to solve a problem. |
| Proportional Rate Reduction | Proportional Rate Reduction (PRR): Proportional Rate Reduction (PRR) is an algorithm in the TCP protocol used to control the sending rate when network congestion occurs. Smooth rate adjustment avoids fast retransmission due to network congestion and reduces performance fluctuations caused by congestion. The PRR algorithm slows down the rate adjustment process when data packets are lost, resulting in more stable network transmission. *Simply put, the transmission rate indicates how much data can be sent per second. |
| Pacing Profiles | Pacing Profile: Pacing profile is a mechanism used for TCP flow control. It controls the packet sending rate to prevent excessive traffic concentration and congestion in the network. It usually adjusts the interval between sending data packets according to the actual network conditions, ensuring smooth data flow and improving the overall network utilization and performance. |
How to configure global TCP parameters
To change the global TCP parameter settings, type the following command and press Enter:
netsh int tcp set global タグ=値For example, to enable the Receive-Side Scaling state:
netsh int tcp set global rss=enabled.
Recommended settings for global TCP parameters
- enabled = enabled
- disabled/off = disabled
- default = default
| Name | Tag | Recommended settings (values) | Remarks |
|---|---|---|---|
| Receive-Side Scaling State | rss | enabled | If you have a multi-core processor, we recommend enabling it. Most computers currently used in homes use multi-core processors (CPUs). For example, when you buy a computer, you might see a display such as "CPU core 8 cores / 16 threads." These "8 cores" are called multi-core (one or more cores). |
| Receive Window Auto-Tuning Level | autotuninglevel | normal | The receive window auto-tuning level includes:5 levelsAlthough there are options available, the default, Normal, is recommended. |
| Add-on Congestion Control Providers | default | This setting can be changed using the TCP parameters based on the supplemental template. *The display will not change even after the change. | |
| ECN Features | ecncapability | enabled | Enabling the ECN function will reduce network latency, so we recommend enabling it. |
| RFC 1323 timestamp | timestamps | enabled | We recommend enabling this as it can optimize performance when network conditions change. |
| Initial RTO | initialrto | 2000 | In Windows 11 version 24H2, this is set to 1 second (1000). However, if the initial waiting time for the TCP retransmission mechanism is too short, network load may increase and performance may decrease. Conversely, if it is too long, retransmission may be delayed if data loss occurs, resulting in large communication delays. Personally, I recommend setting it to 2 seconds (2000). |
| Receive Segment Coalescing State | rsc | enabled | It is recommended to enable this feature as it will improve network reception efficiency. |
| Non-SACK RTT Resiliency | nonsackrtresilience | enabled | This is an important factor for optimizing TCP performance depending on network conditions, so we recommend enabling it. |
| Max SYN retransmissions | maxsynretransmissions | 3 | If the maximum number of SYN retransmissions is too low, it may be impossible to establish a connection in unstable network conditions such as Wi-Fi. Conversely, if it is too high, it may take a long time to establish a connection and increase unnecessary traffic. Personally, I recommend setting it to "3" ("5" for Wi-Fi). |
| Fast Open | fastopen | enabled | This is a necessary feature to reduce delays in establishing a connection over the network, so we recommend enabling it. |
| Fast Open Fallback | fastopenfallback | enabled | It is recommended to enable this as it ensures that connections are established successfully even in environments that do not support TCP Fast Open (TFO). |
| HyStart | hystart | enabled | We recommend enabling this feature to avoid network load and optimize network connection stability. |
| Proportional Rate Reduction | prr | enabled | This will ensure a stable network. We recommend enabling this setting. |
| Pacing Profiles | pacing profile | off | Normally it is fine to leave it disabled. If you frequently send and receive large amounts of data, or if you are using applications such as real-time communications or video streaming, enabling this feature may improve performance. |
Recommended setting commands
netsh int tcp set global rss=enabled
netsh int tcp set global autotuninglevel=normal
netsh int tcp set global ecncapability=enabled
netsh int tcp set global timestamps=enabled
netsh int tcp set global nonsackrttresiliency=enabled
netsh int tcp set global maxsynretransmissions=3
netsh int tcp set global initialrto=2000
netsh int tcp set global rsc=enabled
netsh int tcp set global fastopen=default
netsh int tcp set global fastopenfallback=default
netsh int tcp set global hystart=enabled
netsh int tcp set global prr=enabled
netsh int tcp set global pacingprofile=off
Command to restore default settings
netsh int tcp set heuristics disabled
netsh int tcp set global rss=default
netsh int tcp set global autotuninglevel=normal
netsh int tcp set global ecncapability=default
netsh int tcp set global timestamps=enabled
netsh int tcp set global nonsackrttresiliency=default
netsh int tcp set global maxsynretransmissions=4
netsh int tcp set global initialrto=1000
netsh int tcp set global rsc=enabled
netsh int tcp set global hystart=default
netsh int tcp set global prr=default
netsh int tcp set global pacingprofile=default
About Pacing Profiles
| value | Description |
|---|---|
| off or default | No paging. |
| initialwindow | Paces the initial congestion window. |
| slowstart | Only pace during the slow start. |
| always | Always pacing. |
There is no need to enable it on a typical home or small office network.
*In environments where delays and packet loss rarely occur, there is little benefit to enabling this setting.
About the Receive Window Auto-Tuning Level
| Receive Window Auto-Tuning Level | Description |
|---|---|
| Normal (default) | Configure a larger TCP receive window to accommodate almost all scenarios. |
| Disabled | Sets the TCP receive window to its default value. |
| Restricted | Configures the TCP receive window to grow beyond its default value, but limits such growth in some scenarios. |
| Highly Restricted | Set the TCP receive window larger than the default value, but do so very carefully. |
| Experimental | Configure a larger TCP receive window to handle extreme scenarios. |
I have tested the receive window auto-tuning level many times, and setting it to anything other than the default reduces communication speed.
Therefore, we recommend the default setting of Normal, which automatically expands the receive window when necessary to maintain optimal communication speed in any communication environment.
Configuring TCP parameters based on supplemental templates
Here we will change the congestion control provider currently in use.
In the default settings of Windows 11, the congestion control provider is set to "CUBIC".
| Provider Name (Algorithm Name) | Description |
|---|---|
| CTCP | CTCP is a TCP congestion control algorithm developed by Microsoft. It is designed to achieve high throughput, especially over high-bandwidth, high-latency networks (such as long-distance networks). CTCP is a more aggressive algorithm designed to maximize utilization on high-bandwidth networks. |
| DCTCP | DCTCP is intended to be used primarily in networks within data centers. |
| NewReno | When packet loss is detected, the transmission rate is gradually reduced to avoid congestion. |
| BBR | Developed by Google, BBR (Bottleneck Bandwidth and RTT) is an efficient congestion control algorithm, particularly suited to high-bandwidth, low-latency networks, reducing latency. |
| CUBIC | It performs well on large networks, especially those with high bandwidth and latency. CUBIC is a gentler algorithm designed for stable performance in a variety of network environments. High latency refers to the time it takes for data to arrive when the internet is congested or when communicating with a server that is far away. |
The congestion control provider I recommend is "CTCP". By switching to "CTCP", you can expect higher throughput than with "CUBIC".
High throughput benefits:
- You can watch videos smoothly and download large files quickly.
- Even if many people use the Internet at the same time, it can be used comfortably.
Setting the congestion control provider to "BBR" may improve download and upload speeds, but may cause issues in some environments.
For example, you may not be able to connect to the Internet via a proxy server, or you may not be able to start a virtual machine in an environment using Hyper-V.
Check your current congestion control provider
To check your current Windows PowerShell, type the following command and press Enter:
Get-NetTCPSetting | Select SettingName, CongestionProviderA list of congestion control providers will then be displayed, so check the list to the right of "Internet."
Change the congestion control provider
To change the congestion control provider, type the following command and press Enter:
netsh int tcp set supplemental Template=Internet CongestionProvider=プロバイダー名For example, if you want to change it to "CTCP"
netsh int tcp set supplemental Template=Internet CongestionProvider=ctcp.
After making the change, please check your current congestion control provider again.
If you want to revert to the default, type the following command and press Enter:
netsh int tcp set supplemental Template=Internet CongestionProvider=Now that you have completed the network optimization for Windows 11, try checking the difference between before and after the changes.
About Internet Speed Measurement
Internet speed measurement results vary greatly depending on the site you use and the time of day you measure.As a reference valuePlease capture it.
The two sites I use to test speeds are:
- Internet Speed Test (Google)
https://www.google.com/search?q=speedtest - Broadband Speed Test (Line Speed/Communication Speed Measurement Diagnostic Site)
https://www.bspeedtest.jp
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