AMD Radeon RX 6400 Review and Tested on PCI-Express 3.0

AMD Radeon RX 6400 Review and Tested on PCI-Express 3.0 Today, we are testing the performance impact of PCI Express Gen-3 on the entry level Radeon RX-6400 graphics card, which we already reviewed last week.

Until a few of generations ago, the notion that PCI Express bandwidth is limiting their performance of an entry-level graphics card would have come across as absurd, but times already changing. Recently, GPU vendor’s have been lowering their PCI-Express lane count of their entry mainstream GPU’s in a bid to lower the pin count and reduce the traces on the PCB.

For the Radeon RX-6400, this means a PCI Express-4.0 x4 bus interface. Bandwidth already comparable to PCIe 3.0 x8 or PCIe-2.0 x16. By itself, PCI Express-4.0 x4 seems like plenty of bandwidth, 8 GB/seconds per direction, until you realize that you also need a PCIe Gen-4.0 capable processor and motherboard to use it in Gen-4 mode.

That’s Ryzen-3000 Matisse, Ryzen-5000 Vermeer, Core Rocket Lake, and last Core Alder Lake. Entry level parts from both brands are relegated to the PCI-Express Gen-3.0.

If you are experiencing déjà vu, it’s because we recently tested PCI Express scaling of the RX-6500 XT, the slightly bigger sibling of the RX-6400, and drew some interesting conclusions, mainly that PCI Express Gen-3 bites off a big chunk of performance.

In my RX-6400 review, We suggested that the performance hit would be roughly similar but several readers will requested I actually test this theory, so here we go. We are hence testing the RX-6400 in PCI Express Gen-3 mode, and evaluating the performance loss to Gen-4 to see just how much it affects the target audience of the RX-6400: those with entry-level platforms that have PCI-Express Gen-3.




Test System

Test System – VGA 2022.1
Processor : AMD Ryzen 7 5800-X, PBO Max Enabled
(Zen 3, 32 MB Cache).
Motherboard : EVGA X-570 Dark
BIOS 1.03.
Resizable BAR : Enabled on all supported AMD and NVIDIA cards.
Memory : Thermaltake TOUGH-RAM, 16 GB DDR4
@ 4000MHz 20-23-23-42 1T
Infinity Fabric @ 2000 MHz (1:1)
Cooling : Cooler Master Master-Liquid ML240L V2
240 mm AIO.
Thermal Paste : Arctic-MX-5.
Storage : 2x Neo Forza NFP455 2 TB M.2-NVMe SSD.
Power Supply : Seasonic Prime Ultra Titanium 850W.
Case : darkFlash-DLZ31 Mesh
Operating System : Windows 10 Professional 64bit
Version-21H2 (Nov 2021 last Update).
Drivers : AMD : 22.3.1 WHQL.
NVIDIA : 511.79 WHQL.



Hopefully this article AMD Radeon RX 6400 Review and Tested on PCI-Express 3.0 can be benefit and useful.