Everything About iPerf3 Speed Test [2025 Updated]

Ever get that slow-internet frustration? iPerf3's your friend! It's a simple tool to check your network speed, whether you're gaming, streaming, or just moving big files. Basically, it tells you how fast your network really is.

This post walks you through using iPerf3 for speed tests, even for those super-fast 10Gb connections. If you're looking for even more power, we'll also talk about Raysync, a tool built for seriously fast file transfers. Think of it as your guide to getting the most out of your network.

What Is iPerf3 Network Speed Test

iPerf3 is an open-source network performance testing tool that allows users to measure bandwidth, detect congestion, and analyze data transfer speeds between two devices.

Developed by ESnet (Energy Sciences Network), it is widely used by network administrators, IT professionals, and tech enthusiasts to evaluate local and wide-area network (LAN/WAN) performance.

Unlike traditional internet speed tests, which only provide a rough estimate of download and upload speeds, iPerf3 provides detailed insights into network efficiency, jitter, and packet loss.

It allows users to simulate real-world network conditions by running tests with TCP, UDP, and SCTP protocols, making it a go-to solution for network troubleshooting and optimization.

Key Features of iPerf3:

• Cross-Platform Compatibility – Available for Windows, Linux, and macOS.
• Supports Multiple Protocols – It works with TCP, UDP, and SCTP.
• Bidirectional Testing – Measures speed in both send and receive directions.
• Customizable Parameters – Users can adjust buffer sizes, bandwidth limits, and parallel connections.
• Detailed Performance Metrics – Provides real-time statistics on latency, jitter, and throughput.

iPerf3 test bandwidth is commonly used by network administrators, IT professionals, and tech enthusiasts to monitor LAN, WAN, and internet speed performance. Whether you need to test a home network, a data center, or a cloud server, iPerf3 provides detailed insights into your connection quality.

How to Perform the iPerf3 Network Speed Test

Performing an iPerf3 network speed test is super simple. It helps you measure your network’s bandwidth, latency, and overall performance. Whether you are testing a local network (LAN), a wide-area network (WAN), or internet speed, iPerf3 provides accurate results.

By following these few quick steps, you can easily evaluate your connection’s reliability and efficiency:

Step 1: Install iPerf3

Download and install iPerf3 on the server and client devices from the official website or package manager.

Step 2: Set Up the Server

Run the following command on the server device to listen for incoming tests:

iperf3 -s

This will start iPerf3 in server mode.

Step 3: Run the Test from the Client

On the client device, run the test by specifying the server’s IP address:

iperf3 -c [server_ip]

This will initiate a default 10-second bandwidth test using TCP.

Step 4: Test UDP Bandwidth (Optional)

For UDP performance measurement, use:

iperf3 -u -c [server_ip] -b 100M

This tests with a 100 Mbps bandwidth limit.

Step 5: Analyze the Results

iPerf3 will display network speed, packet loss, and jitter in real-time.

What Is the Limit Bandwidth for iPerf3

By default, iPerf3 does not impose bandwidth limits on TCP tests—it will use the maximum available speed. However, you must manually specify a bandwidth limit using the -b flag for UDP tests.

Key Bandwidth Limitations:

• TCP tests: No bandwidth cap (limited only by network hardware and congestion).
• UDP tests: Requires a defined bandwidth value (e.g., -b 500M for 500 Mbps).
• System constraints: Network adapters and CPU performance can impact results.

For those looking to test 10GB connections with the iPerf3 10 GB test, it’s recommended to:

1. Use multiple parallel streams (-P flag) to fully utilize bandwidth.
2. Disable TCP window scaling (-w flag) for better control over bandwidth allocation.

We Help You Breakthrough the Limit of Bandwidth - Raysync

While iPerf3 is great for testing, it does not optimize data transfer speeds. This is where Raysync enters the picture.

Raysync is an enterprise-level high-speed file transfer solution that ensures maximum bandwidth utilization for large-scale data transfers. Unlike iPerf3 test speed, which simply measures speed, Raysync accelerates transfers using advanced transmission protocols.

Request a Free Trial

Pros of Raysync:

• Maximizes bandwidth efficiency without manual tuning.
• Transfers large files at ultra-high speed (even on poor networks).
• Supports multi-threading to enhance transfer speeds.
• Encrypts data for secure enterprise-grade transfers.
• Optimized for cloud storage and remote collaboration.
• Integrates with existing IT infrastructure seamlessly.
• Offers a simple web-based interface for easy operation.

Con of Raysync:

• Paid solution (not open-source like iPerf3).

Pricing Model of Raysync:

Along with a 7-day free trial, Raysync offers flexible pricing plans based on usage:

	Raysync Cloud	SMB	Enterprise
Cost	$99/ Month	$1,599/ Annual	Tailored Plans
Service	Cloud	On-premise	On-premise
UDP Bandwidth	1Gbps	1Gbps	By license
Storage Capacity	1 TB	Unlimited	Unlimited

Final Words

iPerf3 checks your network speed, great for finding problems. But it won't make transfers faster. For that, try Raysync. It's built for speed, security, and big files. If you need real, fast file transfers, skip the test and use Raysync.