Modders have found a way to cut the huge performance cost of NVIDIA's DLSS 5 Neural Rendering. The fix involves reworking the DLSS 5 rendering order so that neural rendering runs before upscaling. The mod, called Neural Upstream and built by matiasLombo, now works through DLSS5-Autopilot, a community tool similar to DLSS 5 Swapper, that runs Neural Rendering in games NVIDIA never officially supported. A Redditor tested this fix on an RTX 4080 in Assassin's Creed Shadows at 4K with DLSS Performance. Switching from NVIDIA's standard pipeline to Neural Upstream reportedly pushed frame rates from 31 FPS up to around 50 FPS, compared to 63 FPS with the effect off entirely.
The trick comes down to where NVIDIA placed Neural Rendering in the pipeline. It normally runs last, on the fully upscaled 4K frame, which is why the cost balloons at higher resolutions. This is an issue the modders already ran into when they first got Neural Rendering working on RTX 40-series cards. Neural Upstream instead applies it to the lower-resolution frame before DLSS Super Resolution scales it up, similar to how Performance and Quality presets already work for regular upscaling. It looks like NVIDIA leaned toward image fidelity in the standard application, so the trade-off is a further hit to visual quality on top of DLSS 5's existing "uncanny valley" issues.