The USB 4.0 Standard — The Answer To Bandwidth Optimization For Video And Data
We have gone through several versions of the USB standard in the last two decades. There were 2 versions of USB 3.1 and 4 versions of USB 3.2. Each iteration increases bandwidth, allowing more data to be transferred between devices. The significant gains leads to faster access to content like video, which are bandwidth intensive. The interface connector type of the USB cable has also changed from Type A to Type C. The USB-C connector can be inserted in any orientation to the socket or receptacle, so there is no wrong or right way to insert it. With your typical USB-A and microUSB connectors, you have to orient the connector correctly or else it won’t connect to the device. USB-C also uses the same type of connector on both ends, making it easier for manufacturers to adopt a standard design for sockets and cables for devices.
The next iteration of USB, simply called USB 4, will be the latest standard. It was first announced in 2019, as it underwent testing for quality assurance and design specifications. This also allowed time for engineers to learn about the design for their products based on the specifications. The good thing about USB 4 is not just the speed, but also better resource allocation for video and data. This will allow power users to connect more devices and get the best performance at the same time. There are other benefits as well, which will be mentioned.
USB 4 has the following technical specifications:
Data Rate: 40 Gbps
Supported Protocols: Superspeed+, Thunderbolt 3, DisplayPort 1.4a, PCIe
Interface Type: USB-C
Encoding: Dual Lane (8b/10b, 128b/132b, 64b/66b, 128b/132b)
Power Delivery: 7.5W (5V, 1.5A) up to 100W (20V, 5A) per port
Data Transfer Modes:
Once the standard is adopted by manufacturers and vendors, the specifications will be used for hardware design in products that support USB 4.
We can expect the following from USB 4:
- Faster Data Transfers — The full capacity of the cable’s bandwidth supports up to 40 Gbps or 5 GB/sec (5 Gigabytes of data). This will benefit power users like editors and graphics designers since they can work with larger file sizes from external devices at faster speeds. Files stored on a hard drive connected via a USB 4 cable can transfer more data to the application, allowing better rendering times.
- Compatibility With Thunderbolt 3 — Intel has announced that it will provide the Thunderbolt 3 specification protocols to the USB Promoter Group, allowing USB 4 to be compatible with Thunderbolt 3. It is a sort of type of deal, because it is only optional for USB 4 hosts and devices. The device manufacturer must build their product for full compatibility with Thunderbolt 3. Many will probably support it for compatibility with existing devices. Intel has removed royalties for Thunderbolt 3, allowing manufacturers to use their own controller implementations as long as it follows Intel’s standards.
- Video And Data Bandwidth Optimizations — This is perhaps one of the best features of USB 4. The amount of resources used by video and data can be dynamically adjusted. This allows power users to connect a display monitor and work with files at the same time. Editors come to mind regarding this, since they will use video and data simultaneously. With USB 4 using a maximum rate of 40 Gbps, if 25 Gbps are required for video, it will be allocated that amount. The rest will then be provided for data, thus it optimizes the sharing of bandwidth. This can significantly reduce bottlenecks in the digital workflow process for video and graphics editing. Another thing about this feature is that video can use 40 Gbps bidirectional lanes, but it usually just needs to transmit in one direction (from computer to display). Rather than wasting bandwidth, USB 4 allows using the additional 40 Gbps lane’s bandwidth available for 80 Gbps total, by sending video in just one direction.
- Better Power Delivery — All USB 4 devices need to comply with USB PD (USB Power Delivery). This allows for better power management and for devices to use higher wattage. Devices can charge faster with more wattage. USB PD supports up to 100 W, so it can be used for charging smartphones, tablets and laptops much faster.
- Higher Resolutions — Support for DisplayPort Alt Mode 2.0 spec, allows powering either 3x 10K monitors or 1x 16K monitor at 60Hz. This means that higher resolution and refresh rate displays like 8K and 16K will be supported. This allows 8K at 60Hz with HDR, 4K at 144Hz with HDR, or even 16K (15360 x 8460) at 60Hz with compression.
- Backward Compatibility — All USB iterations are supported, but not the maximum data rate. A USB 3.1 device will not be able to transfer up to 40 Gbps as it is limited by its original design. Older USB devices will only operate at their rated speed. The legacy cables will need an adapter to support the interface connection to USB-C.
The typical product cycle takes from 12 to 18 months. USB 4 devices will probably start appearing later in 2020 or early 2021, but things can change between now and then. By the time vendors support it, there should be a market for these new devices. As more and more devices are being connected to computers, optimizing the bandwidth for each device is going to be beneficial. Even gamers can take advantage of this. For regular users, charging devices much faster would be ideal. For power users, they can connect multiple monitors, eGPU and storage devices at the same time. They can transfer data and also power up those devices using USB 4.
The USB Promoter Group will spell the new standard “USB4”. The organization wants to keep the naming conventions as simple as possible to avoid the previous confusion with USB 3. That means there won’t be a need for iterations like 4.1, 4.2 or 4.3.1, etc. From the sound of that it looks like it will be easier to remember the nomenclature in the overall terminologies. One thing the organization did stress is that USB 4 is also a new architecture which will focus more on simplicity rather than techie buzzwords. The new generation of USB will be about performance first, naming conventions later.