PCIe, or Peripheral Component Interconnect Express, is one of the most useful interfaces in the computing space. Compatible with most modern systems, be it a laptop, desktop, gaming handheld, or even an SBC, PCIe lets you pair graphics cards, RGB controllers, Ethernet cards, USB hubs, SSDs, and a variety of other peripherals to enhance the functionality of your PC.
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Currently, PCIe 5.0 remains the latest standard for most components besides GPUs, which still utilize PCIe 4.0 buses. Interestingly, PCI-SIG, the consortium that oversees the development of this game-changing interface, has already released plenty of information about PCIe 6.0. So, this article will go over everything we know so far about the blazing-fast addition to the PCIe ecosystem.
What is PCIe 6.0?
PCIe 6.0 is the next-generation standard that, just like its predecessors, aims to double the data transfer speeds for peripherals that utilize the PCIe interface on motherboards. Besides doubling the bandwidth of PCIe 5.0, the upcoming PCI express Gen 6 interface will also introduce new features to reduce latency and improve the efficiency of your favorite PCIe peripherals. Like its previous iterations, the next-gen interconnect standard will be backward compatible with components that support PCIe 5.0 or older interfaces.
PCIe 6.0: What we know so far
Higher bandwidth and transfer speeds, despite the same frequency as PCIe 5.0
Up until now, every subsequent addition to the PCIe family has doubled the data transfer rates and bandwidth of its predecessor. PCIe 6.0 follows this tradition and is capable of providing a raw data rate of 64 GT/s alongside a maximum bidirectional bandwidth of 256 GB/s for x16 data lanes.
|
PCIe generations |
Bandwidth |
Transfer rate |
Frequency |
|---|---|---|---|
|
PCIe 4.0 (x16) |
64GB/s |
16 GT/s |
8GHz |
|
PCIe 5.0 (x16) |
128GB/s |
32 GT/s |
16GHz |
|
PCIe 6.0 (x16) |
256GB/s |
64 GT/s |
16GHz |
However, the key difference between PCIe 6.0 and previous entries in the series is that the frequency has remained unchanged since PCIe 5.0, meaning the upcoming architecture will also operate at a frequency of 16GHz. The reason for this change can be attributed to the new PAM4 mechanism added to the PCIe 6.0.
PAM4 signaling
Before PCIe Gen 6, previous iterations utilized the Non-Return-to-Zero signal modulation technology. The older NRZ (or PAM2) standard possesses two amplitude levels, 0 and 1, per clock interval. In simpler terms, it can only send voltage across two levels for every unit interval.
Meanwhile, the Four-level Pulse Amplitude Modulation technique bumps this number to 4 logic levels, effectively doubling the number of bits that could be sent every clock interval. For the average user, this means PAM4 will enable PCIe 6.0 devices to achieve double the data transfer speeds of PCIe Gen 5 without any change in frequency.
New error detection and correction mechanisms
On paper, PAM4 sounds like a solid addition to the PCIe ecosystem, right? Unfortunately, the new modulation method has a major drawback, namely a monumental increase in the possibility of errors. As such, PCI-SIG has added the 256-byte Flow Control Unit (FLIT), which reserves six bytes for Forward Error Correction and another four bytes for Cyclic Redundancy Check.
While these topics deserve an article of their own, the simplest way to explain them is that the new FLIT-based mechanisms will curb the frequency of errors caused by the transition to PAM4. The FEC includes extra bits of data that are used to correct errors, which are then checked for errors with the help of four CRC bytes.
When can we expect PCIe 6.0 components?
After reportedly developing the technology for three years, PCI-SIG released the specifications of PCIe 6.0 in January 2022. While we haven’t seen any components that support this feature-laden standard yet, PCI-SIG earlier claimed that PCIe 6.0-compatible devices should be released sometime this year.
If past trends are anything to go by, the first wave of hardware that supports PCIe 6.0 connectivity will probably include motherboards and SSDs. But given how hot some of the best PCIe 5.0 SSDs can get, it’ll be interesting to see what provisions manufacturers will utilize to prevent the faster PCIe 6.0 from overheating.
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Do I need a heatsink for PCIe 5.0 SSDs?
PCIe 5.0 SSDs require a heatsink for optimal performance, but whether you need to buy a heatsink alongside a PCIe 5.0 drive is something else.
Meanwhile, things are rather dire on the GPU side of things. Despite being two years old at this point, we still haven’t seen a single consumer-grade graphics card supporting PCIe 5.0 connectivity, and even the most powerful GPUs continue to utilize the outdated PCIe Gen 4 interface. Although the upcoming Nvidia RTX 5000 and Intel Battlemage GPUs are rumored to support this standard, I would be surprised if PCIe 6.0 makes its way into the graphics card market before 2026.