PCIe 5.0 doubles PCIe 4.0's bandwidth, but your graphics card barely cares

The PCIe 5.0 standard doubles the bandwidth of its predecessor, PCIe 4.0. This upgrade sounds significant, but the reality is that many graphics cards, even high-end ones, don't fully utilize the extra bandwidth. For instance, an RTX 4090, a PCIe 4.0 GPU, wouldn't benefit from the increased bandwidth offered by PCIe 5.0. Even if you upgraded to a newer GPU like the RTX 5090, which boasts impressive memory bandwidth of almost 1.8TB/s, PCIe 5.0's theoretical bandwidth of 63GB/s still wouldn't significantly impact its performance.

The GPU has its own memory interface which is much faster than PCIe for accessing textures, frame buffers, and other game data already stored in VRAM. Data transfers between system RAM and VRAM are the actual performance bottlenecks, and unless these transfers are limited by available bandwidth, PCIe 5.0's increase doesn't translate to noticeable performance gains.

In fact, PCIe 5.0's performance gains are more relevant for entry-level GPUs that use fewer PCIe lanes. If your GPU only has 8 PCIe lanes, switching to a PCIe 5.0 motherboard will halve its available bandwidth and may lead to stuttering if the GPU needs more memory than it has available.

In summary, if you're considering a motherboard upgrade for PCIe 5.0 support, it's not worth it unless your GPU has fewer PCIe lanes or lacks sufficient VRAM. For most high-end GPUs, PCIe 5.0 doesn't offer meaningful performance improvements. A more critical upgrade path is getting a GPU with ample VRAM, as data transfers between system RAM and VRAM are the actual performance bottlenecks.