AMD Radeon RX 6400 suffers a double digit performance decrease on PCIe 3.0

TechPowerUp has put the AMD Radeon RX 6400 through its paces on the aging PCIe 3.0 interface and the results are abysmal.

It is no secret that the AMD RX 6400 isn’t a powerhouse. The card is based on a cut-down Navi 24 GPU with a measly 12 compute units, 4 GB of GDDR6 VRAM, and 128 Gbps of memory bandwidth. In essence, the RX 6400 is considerably slower than its bigger brother the RX 6500 XT which was already a weak board. Unsurprisingly, the performance of RX 6400 is even duller when used in a PCIe 3.0 system.

According to TechPowerUp, the RX 6400 registers an average hit of about 14% on 1080p and 1440p combined when the card is used with a PCIe 3.0 interface. For instance, in PCIe 4.0 mode, the RX 6400 only managed to push out 20 fps when playing Assassins Creed: Valhalla on 1080p/Ultra settings. The already stinky frame rate dropped to 13.4 fps when using PCIe 3.0, a decrease of 33%.

Moving on to 1440p, the RX 6400 ran AC: Valhalla at an unplayable 8.5 fps on PCIe 4.0 and dropped to 6.4 fps on PCIe 3.0, a hit of almost 25%.

The reason why the RX 6400 suffers on PCIe 3.0 is because the card has only 4 PCIe 4.0 lanes. Almost all modern GPUs, except for the likes of RX 6500 XT, have four times the lanes present on the RX 6400. Reducing PCIe lanes on Navi 24 was a cost-cutting decision by AMD. Although it did work as the RX 6400 only costs US$159, it has handicapped the board and made it almost useless for modern AAA gaming.

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