Introduction

AMD launched the Radeon RX 5700 XT graphics card today. Be sure to check out our full reviews of the RX 5700 XT and its little sibling, the RX 5700. The two are based on the new 7 nm "Navi 10" silicon. With the introduction of each new graphics architecture, we are curious about its ability to utilize PCI-Express. For close to 16 years, PCI-Express dominated client-segment PCs as the definitive graphics card bus standard. Navi isn't an enthusiast-segment GPU, but gets a PCI-Express feature article from us because it's the first client-segment graphics card to feature the new PCI-Express 4.0 x16 interface. The new bus pushes up to 16 Gbps of data per lane, which translates to 256 Gbps of memory bandwidth, double that of PCI-Express 3.0 x16.

A graphics card from the performance segment may not need that much bandwidth, but what it offers instead is bandwidth in scenarios where there are fewer PCIe lanes. Think crypto-mining motherboards of the future, or even using a single "Navi" graphics card at PCI-Express 4.0 x8 bandwidth while allocating the remaining eight lanes for another bandwidth-hungry device, such as an M.2 NVMe RAID riser card that supports PCIe gen 4.0.



The Radeon RX 5700 XT is fully backwards compatible with older generations of PCIe. To use PCIe gen 4.0, just having this graphics card isn't enough as you also need a motherboard and CPU combo that supports PCIe gen 4.0. Currently, the combination of a 3rd generation Ryzen "Matisse" processor and a motherboard based on the AMD X570 chipset is the only gen 4.0 platform. It is expected that Intel's next-generation Core "Ice Lake" processor and its companion chipset will support PCIe gen 4.0.

In this review, we test the performance scaling of the Radeon RX 5700 XT across generations of PCIe. A reference-design RX 5700 XT is paired with an ASRock X570 Taichi motherboard and an AMD Ryzen 9 3900X processor. We compare its performance at PCIe gen 4.0 x16 with PCIe gen 3.0 x16 and PCIe gen 2.0 x16 to tell you whether PCIe gen 4.0 makes a real-world difference in terms of performance.

Test System

Benchmark scores in other reviews are only comparable when this exact same configuration is used.

• All games and cards are tested with the drivers listed above—no performance results were recycled between test systems. Only this exact system with exactly the same configuration is used.
• All games are tested using the same game version.
• All games are set to their highest quality setting unless indicated otherwise.
• AA and AF are applied via in-game settings, not via the driver's control panel.
• Before starting measurements, we heat up the card for each test, to ensure a steady state is tested. This ensures that the card won't boost to unrealistically high clocks for only few seconds until it heats up.

Each game is tested at these screen resolutions:

• 1920x1080: Most popular monitor resolution.
• 2560x1440: Intermediary resolution between Full HD and 4K, with reasonable performance requirements.
• 3840x2160: 4K Ultra HD resolution, available on the latest high-end monitors.

Our exhaustive coverage of AMD's 7/7 Launch Day includes the following content:
AMD Ryzen 9 3900X 12-core processor | AMD Ryzen 7 3700X 8-core processor | AMD Radeon RX 5700 XT graphics card | AMD Radeon RX 5700 graphics card | AMD Zen 2 Memory Performance Scaling | Ryzen 3900X and 3700 on X470 vs X570 platforms | Radeon RX 5700 XT Navi PCI-Express 4.0 Performance Scaling | ASRock X570 Taichi motherboard | ASUS Prime X570-Pro motherboard