Keysight Technologies, Inc. (NYSE: KEYS) today introduced System Designer for USB, a comprehensive design solution that supports the latest USB4® standards—Gen2, Gen3, and Gen4. Tailored for high-speed digital USB applications in personal computers, mobile devices, and edge AI, the platform delivers an integrated environment for modeling, simulating, and validating USB4® interfaces. By combining a smart workflow with simulation-driven virtual compliance testing, System Designer for USB aims to accelerate time-to-market and reduce design risks associated with complex multi-channel, multi-level USB configurations.

As data throughput demands rise, designers face the challenge of ensuring reliable USB communication for large-scale data transfers. The USB4® specification addresses this need by delivering speeds up to 120 Gbps and employing three-level pulse-amplitude modulation (PAM3) within the popular USB-C® connector. System Designer for USB leverages these modern standards to provide early-stage validation of signal integrity, link training, and performance, helping engineers identify bottlenecks and compliance issues before hardware prototypes are available.

Key features of System Designer for USB include a streamlined environment that simplifies the setup of multi-link, multi-lane, and PAM3 configurations through a guided, smart workflow. The solution’s USB Algorithmic Modeling Interface (AMI) modeler supports both Non-Return-to-Zero (NRZ) and PAM3 modulation schemes, enabling rapid implementation of high-speed USB links. Integrated compliance-test simulations automate critical validation steps, reducing design iterations, minimizing re-spins, and cutting overall development costs. Simulation-driven insights help engineers resolve signal integrity challenges early and efficiently.

One-sentence summary; What is USB4

USB4 is the USB-C form factor for connecting; fully supports the Thunderbolt 3 specification, all wrapped up using the USB 3.2 specification.

USB4 has four benefits over prior versions of USB.

Maximum speed of 40Gbps. Using two-lane cables or a set of cables, devices may operate at up to 40Gbps, the same speed as Thunderbolt 3. Keep in mind there is a big difference between Mb and MB. Mb is megabits, not megabytes (MB). For example, 8Mb is about 1MB of data. As a reference, a typical MP3 audio file is about 3MB (megabytes). 5,000MB/second is the theoretical maximum speed of USB4.

USB4 supports DisplayPort 2.0. DisplayPort 2.0 cables feature 80Gbps bandwidth, making it possible to display ultra-high resolutions at previously impossible refresh rates. DisplayPort 2.0 can handle up to two 4K screens at 144Hz simultaneously, or an 8K display at up to 85Hz natively, with no form of image compression. This is possible because USB4 can use all eight data lanes at the same time.

Compatible with Thunderbolt 3 devices. USB4 is a protocol which supports all the specifications of Thunderbolt 3; however, Thunderbolt 3 is capable of 100 watts of bi-directional power delivery and not all manufacturers who support USB4 will include the full power implementation of Thunderbolt 3.

More efficient resource allocation. USB4 devices use a process called protocol tunneling, which optimizes the use of DisplayPort, PCIe, and USB packets at the same time while allocating bandwidth to improve efficiency. This approach can deliver better performance across multiple connected devices using different protocols.

USB4 will only operate through a USB-C type physical connector. USB4 peripherals will most likely not support older USB Type-A ports because the connection speeds and power delivery mechanisms will not be available. Although USB4 is backward compatible with all other USB protocols, it does not mean older standards will receive the improved benefits. For example, if you connect a Type-A 5Gbps USB 3 port using an adapter, the speed and power will drop to the lowest common denominator.

Some notable comments:

Device and host manufacturers are not required to pay Intel royalties when implementing USB4 technology. This improves the chance of mass adoption. However, there is a catch between manufacturing USB4 devices and making products fully USB4 compliant. Specifically, the Thunderbolt compatibility specification may become part of the product requirements for using the USB4 logo. This could mean a consumer buys a laptop with USB4 and later discovers it does not work with a Thunderbolt 3 peripheral.

It is important to know Thunderbolt 3 and Thunderbolt 4 are logo-certified programs from Intel which cost manufacturers time and money. While a USB4-powered computer may work with 40Gbps devices or even those labeled as Thunderbolt, this may not be obvious because the product did not go through certification. The opposite can also be true: a USB4 device may not support Thunderbolt due to the cost required for certification.

USB4 has two speed tiers. As with Thunderbolt, a USB4 product may not support the full 40Gbps specification. 40Gbps is the theoretical maximum speed, but many devices will use the lower 20Gbps standard because manufacturing costs are lower, resulting in a lower price for consumers. If speed is a priority, check the specifications of the USB4 product before purchasing. At the time of writing, most USB4 products that support 40Gbps are cables and PCIe adapter cards.

Why the USB4 name?

An online article summarizing an interview with Brad Saunders, CEO of the USB Implementers Forum (USB.org or USB-IF), indicated the lack of a space between “USB” and “4” is intended to move focus away from version numbers and toward branding. This branding change makes sense, but the long history of USB versions will likely continue to cause confusion.

USB 3.2, the most recent widely deployed standard at the time of its introduction, supports maximum transfer speeds of up to 20Gbps under its fastest configuration. USB4 builds on that foundation and raises the ceiling to 40Gbps, with the newer USB4 Version 2 specification extending bandwidth even further to a theoretical 80Gbps. Put another way, 80Gbps is equivalent to moving roughly 10,000MB of data in a single second, or about 10GB per second.

Keep in mind this is all theoretical maximum throughput. Real-world performance will always be lower due to protocol overhead, controller limitations, cable quality, and storage speed. That gap between headline numbers and actual transfer rates has always existed and will continue to do so.

USB4 is built on Intel’s Thunderbolt technology, a high-speed interface Apple strongly promoted starting around 2012. While Thunderbolt delivered excellent performance, licensing costs and strict certification requirements kept accessory prices high and limited widespread adoption. Intel’s long-term goal was always to merge Thunderbolt into USB, bringing higher speeds to the mainstream at more affordable price points.

USB4 maintains backward compatibility with USB 3.2, USB 2.0, and Thunderbolt 3 devices. Because the standard fully embraces the USB-C connector and unifies multiple protocols, manufacturers can design fewer ports while supporting more use cases. As USB4 adoption increases, faster cables, docks, and storage devices are already becoming more common and less expensive.

USB4 devices are also required to support USB Power Delivery, which intelligently manages charging and power negotiation. This allows everything from smartphones to high-performance laptops to draw the correct wattage safely and efficiently from the same port.

Early USB4 products began appearing in the market in 2020, and today the ecosystem is steadily expanding as controllers, cables, and host systems mature. This post was originally prompted by the release of the finalized specification from the governing body, USB-IF, and the momentum behind USB4 has only increased since then.

In the news, Intel has handed over its specification for high-speed Thunderbolt technology to the USB Implementers Forum (USB-IF), the organization responsible for developing and managing USB standards.

The USB4 specification will follow the current USB 3.2 standard, although an exact public release date had not yet been defined at the time of the announcement.

USB4 doubles the bandwidth of USB 3.2 and supports theoretical maximum transfer speeds of up to 40Gbps.

USB4 also enables multiple data and display protocols to operate simultaneously. This means a single cable can be used to transfer data, drive an external display, and deliver power to connected devices.