Average 14 percent less FPS with PCI-E 3.0

AMD’s Navi lineup has mostly been convincing in tests so far and is the first AMD architecture in a long time that Nvidia can stand up to. Only the Navi 24 models, which mark the entry, are somewhat problematic. They have a small mobile GPU that is connected with just four PCI-E lanes. As long as these lanes support PCI-E 4.0, the bandwidth is sufficient, but if the graphics card is used as an upgrade from an older system with PCI-E 3.0, the interface can mean significant performance disadvantages.

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In our test with the Radeon RX 6500 XT, performance deficits of negligible 0.5% up to almost 37% were measured, which spoil the gaming fun. Below the RX 6500 XT, AMD recently placed the Radeon RX 6400, which seems to suffer from the same problem. It also has four GiB graphics memory and a PCI-E 4.0 interface with only four connected lanes.

Techpowerup’s test confirms the assumptions about AMD’s smallest RDNA 2 card. While the low-lane design approach is not necessarily bad for a mobile solution and offers advantages, the performance of a desktop graphics card suffers measurably as a result. Over 25 games, the Radeon RX 6400 loses an average of 14 percent with PCI-E 3.0 compared to PCI-E 4.0. That means such performance deficits are imminent on all pre-11th Gen Intel platforms and all pre-Zen 2 AMD platforms. However, the bad thing is not the average losses, but the worst-case games. The frame rate drops by 35% in Assassin’s Creed Valhalla and God of War and by 30% in Doom Eternal, making it difficult to recommend the Radeon RX 6400 for older platforms either.

Source: tech powerup