The Radeon RX 6400 loses up to 14% performance in PCIe 3.0

In a recent test conducted by TechPowerUp of the new AMD Radeon RX 6400 graphics card, using the card in the PCIe 3.0 interface compared to PCIe 4.0, the performance decreases by 14% depending on the resolution.

The Radeon RX 6400 is the cheapest card in AMD’s Radeon RX 6000 series for desktops., powered by the trimmed Navi 24 chip, initially designed for laptops. Just like its big brother, the Radeon RX 6500 XT, this card only has four PCIe 4.0 lanes as a way to save money. The Radeon RX 6400 has an approximate 13% reduction in core count and memory bandwidth compared to the Radeon RX 6500 XT.

The graphics card only has 768 cores and 128GBps of memory bandwidth, thanks to a reduction in GDDR6 memo speeds to 16Gbps. However, the memory capacity remains the same at 4 GB. But the main strength of the Radeon RX 6400 is its power consumption. It has half the power consumption of the Radeon RX 6500 XTaround 53W, which makes this GPU very useful in small power-constrained systems.

Across the 24 games tested, the Radeon RX 6400 running PCIe 3.0 experienced an average 14% drop in performance at 1080P and 1440P compared to PCIe 4.0. Results at 4K were even worse, with a 23% performance deficit. This last one is fine, since it is not a card to play at 4k.

Some of the worst performers included F1 2021 and Doom Eternal, which had a 79% and 43% difference, respectively, in 1080P performance. At least the other titles tested were in the 14% loss range.

Tests for the Radeon RX 6500 XT showed almost the same results, showing a 13% performance deficit when comparing PCIe 3.0 to PCIe 4.0.

The Radeon RX 6400’s PCIe 3.0 was nearly 20% slower than the GeForce GTX 1650, which runs on the same PCIe 3.0 interface and runs in a 16-lane configuration. However, when installed on a PCIe 4.0 interface, the Radeon RX 6400 performed similarly to the GeForce GTX 1650.

Consumers looking for the Radeon RX 6400 need a PCIe 4.0 platform to avoid the severe performance drop of PCIe 3.0. The biggest problem is that consumers who are likely to buy a Radeon RX 6400 have an older system.

If you don’t have access to PCIe 4.0, the best alternative is Nvidia’s GeForce GTX 1650 or even the Radeon RX 570, which is faster than the Radeon RX 6400 and doesn’t require PCIe 4.0 to unlock its full performance.