Article Number: PA-270

his article provides information about the usage and compatibility of PCIe riser cables and extenders with PCIe Gen4 desktop systems.

Introduction

Many modern PC chassis are designed to support aftermarket components that enable users to customize the appearance of their desktop systems. Some examples of aftermarket components include LEDs, case mods, cooling, cables, etc. Although most of these components are widely compatible, some are only compliant for use with specific PC form factors and technology standards.

Aftermarket components that alter data transmission links and/or power connectivity must meet specific system requirements to ensure stable operation. An example of one such component is the PCIe riser cable and extender, used to connect the graphics card to the motherboard allowing the graphics card to be mounted in different positions supported by the PC chassis.

Here is a picture of a typical PCIe riser cable and extender:

Certain PCIe riser cables and extenders when used in some systems may create stability issues during normal operation. Therefore, it is important to review the specifications of the PCIe riser cable and extender to ensure system compatibility and proper use.

Please note that for the purpose of this article, only AMD PCIe Gen 4.0 platform compatibility is covered.

PCIe Gen 4.0 Mode and Compatible Platforms

PCIe Gen4.0 operation is achieved with the following hardware combination:

  1. AMD 3rd Gen Ryzen™ Processors* (see note)
  2. AMD Socket AM4 500 Series Chipsets
  3. PCIe Gen 4.0 Capable Devices

Any riser cables and/or extenders installed between compatible CPUs, chipsets, and PCIe Gen 4.0 devices (i.e. Radeon™ RX 5000 Series graphics) must be PCIe Gen 4.0 compliant and validated by the system vendor to ensure full compatibility.

*NOTE: AMD Ryzen 3 3200G/GE and Ryzen 5 3400G/GE are 2nd Gen Ryzen processors and do not support PCIe 4.0. For more information, please refer to AMD Ryzen desktop processors.

Recommendations

Since many PC chassis currently on the market come with PCIe riser cables and extenders validated only for PCIe Gen 3.0 operation, there may be some system stability issues when used in combination with PCIe Gen 4.0 devices. If you are experiencing stability issues such as choppy mouse movement, BSOD or hangs, please follow the troubleshooting recommendations below to pinpoint the problem:

  1. Change PCIe Slot Configuration setting – The PCIe Slot Configuration option is found in the system BIOS. Change its current setting to Gen 3.0 then save and exit the BIOS. After the system reboots check whether the stability issues persist.
    NOTE! For more information about your system BIOS and settings, please refer to the system/motherboard user manual.
     
  2. Reseat devices – For example, remove the riser cable and extender and install the PCIe Gen 4.0 graphics card directly to the PCIe x16 slot on the motherboard. Ensure that the PCIe slot configuration option is set to Gen 4.0 (or Auto) then check whether the stability issues persist.
    NOTE! Apply this step to any Gen 4.0 devices on your system connected by riser cables and extenders.

If either troubleshooting step resolves your system stability issues, it indicates that the riser cable and extender may not be PCIe Gen 4.0 compliant or potentially malfunctioning if it was not validated by the vendor.

The ideal solution in this case would be to replace the faulty riser cable and extender with one that is PCIe Gen 4.0 compliant and validated for compatibility with your PCIe Gen 4.0 device. If this is not currently feasible, then consider keeping the devices connected directly to the motherboard. However, if direct device connection is not appealing for any reason, you may consider setting the PCIe Slot Configuration option in the BIOS to Gen 3.0, as a workaround.

DISCLAIMER

The information contained herein is for informational purposes only, and is subject to change without notice. While every precaution has been taken in the preparation of this document, it may contain technical inaccuracies, omissions and typographical errors, and AMD is under no obligation to update or otherwise correct this information.  Advanced Micro Devices, Inc. makes no representations or warranties with respect to the accuracy or completeness of the contents of this document, and assumes no liability of any kind, including the implied warranties of noninfringement, merchantability or fitness for particular purposes, with respect to the operation or use of AMD hardware, software or other products described herein.  No license, including implied or arising by estoppel, to any intellectual property rights is granted by this document.  Terms and limitations applicable to the purchase or use of AMD’s products are as set forth in a signed agreement between the parties or in AMD's Standard Terms and Conditions of Sale. GD-18

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