There is no evidence that compute payloads need x16 Gen5 bandwidth to run fully on desktop and HEDT systems, even without NVLink.
PCIe Lanes can severly bottleneck your performance if you don't have enough for your workload. Here's all you need to know about PCIe Lanes.
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Here's everything you need to know about the Best Hardware for GPU Rendering in Octane, Redshift, V-Ray and other modern GPU Render Engines.
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For compute workloads on GPU, it's far more important that GPU has enough bus width and VRAM capacity to process workloads within itself than bandwidth needed to send and receive queries to/from CPU and other peripherals.
Somehow you forgot that TRX50 platform has more physical PCIe lanes directly wired with CPU than Sapphire/Emerald Rapids, which deals with any bottleneck created by traffic via chipset. On TRX50, only necessary I/O peripherals are wired into chipset, everything else has a direct access to CPU.
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As said, both platforms are overkill in terms of Gen5 lanes, Intel's platform more so. It's a marketing gimmick to drive away attention from simple fact that Emerald Rapids is end-of-life platform with no CPU upgrades.