Enabling L4S (Low Latency, Low Loss, and Scalable Throughput) in the GeForce NOW streaming quality settings may help improve the network latency and minimize packet loss while streaming. L4S can be enabled from the GeForce NOW “Custom” streaming quality settings when “Adjust for poor network conditions” toggle is set. If L4S is not available on your network, the L4S setting has no effect and can be disabled.
Does my network support L4S? How do I get L4S?
L4S requires supported network equipment capable of marking packets during network congestion. Reach out to your ISP to confirm L4S availability and inquire about supported home equipment.
L4S requires supported network equipment capable of marking packets during network congestion. Reach out to your ISP to confirm L4S availability and inquire about supported home equipment.
What ISPs are supported?
Comcast (Xfinity) started limited areas in late 2024.
Comcast (Xfinity) started limited areas in late 2024.
How does L4S work?
Network congestion may occur on a network path from data centers to user devices (or user devices to GFN data center), e.g., when multiple network flows compete for limited network resources. This network ‘bottleneck’ is usually found at the entry - and exit - points between a user's home and ISP’s network. Network bottlenecks often lead to increased latency and eventually packet loss.
Network congestion may occur on a network path from data centers to user devices (or user devices to GFN data center), e.g., when multiple network flows compete for limited network resources. This network ‘bottleneck’ is usually found at the entry - and exit - points between a user's home and ISP’s network. Network bottlenecks often lead to increased latency and eventually packet loss.
L4S [RFC 9330] is a new technology that helps achieve consistent and low network delays despite network bottlenecks. L4S isolates latency-sensitive (e.g., GeForce NOW traffic) from unresponsive traffic while ensuring throughput fairness for all applications sharing the bottleneck.
When the L4S toggle is set, GeForce NOW marks its traffic with ECN-Capable Transport (ECT) codepoint in the IP headers. During network congestion, L4S equipment remarks these packets with a Congestion Experienced (CE) codepoint. In response to CE-marked packets, GeForce NOW promptly adjusts the streaming rate to minimize queue build-up and avoid latency increase.
Note: L4S support is currently available for Premium memberships and on native GFN apps for Windows, MacOS, Android, and SHIELD TV.
How can I verify if I am streaming with L4S?
Once you have launched a game on native GFN apps on Windows or MacOS, you can use the GeForce NOW in-stream statistics (Ctrl+N or Cmd+N) to confirm the if L4S is active on your network:
- “L4S: -” indicates an unknown state of L4S support on your network. This will be the expected starting value for all networks.
- “L4S: Active” indicates confirmed active L4S support on your network.
- Note: The value will be “-” until L4S marked packets are detected during network congestion on a L4S enabled ISP with supported equipment.
- “L4S: Inactive” indicates confirmed unavailability of L4S support on your network, or the L4S toggled off in the GeForce NOW streaming settings.
