Amd recently released the entry-level graphics card RX 6400. Like the previous RX 6500 XT, it only supports PCIe 4.0 X4 system interface, with one-way bandwidth of 8GB / s, which is equivalent to PCIe 3.0 X8. Techpowerup conducted an interesting test to investigate the performance of 25 games and three resolutions of Rx 6400 in PCIe 4.0 X4 and PCIe 3.0 X4 modes respectively to see how poor it can be.
Directly look at the summary of results: in PCIe 3.0 mode, the performance of Rx 6400 1080p / 2K resolution has lost 14%, and the performance of 4K resolution has plummeted 23%**
Of course, 2K / 4K resolution is meaningless for this level of card, but it can also explain a trend.
The performance of different games is also quite different, PCIe 3.0 mode in Assassin's Creed: Hall of heroes and God of war has lost up to 35% of the performance, while wizard 3 is almost unchanged, and the latter is mainly some old games**
In addition, for games requiring high-capacity video memory, RX 6400 4GB is easy to be insufficient. At this time, we have to borrow PCIe channel and system memory transmission resources, and PCIe 3.0 will become a bottleneck.
TPU suggests that if you are still using PCIe 3.0 system, such as Intel's 10th generation core or earlier, and AMD's first generation Raptor, do not consider RX 6400. It is not as expensive as the previous RX 570 4GB, and supports complete PCIe 3.0 x16. On the contrary, the game performance can be better, sometimes up to 17% higher than RX 6400**
In addition, RX 570 and even RX 400 series still support FSR, which can further improve performance and image quality.
