Production-safety confirmation for disabling parallel render cvars (UE 5.7)

Development Rendering
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Hi Epic Support team,

We’re seeing improved GPU performance on lower-spec GPUs in UE5.7 when disabling the following cvars:

r.ParallelTranslucency=0
r.ParallelSingleLayerWaterPass=0
r.ParallelVelocity=0
r.ParallelMeshDecal=0

Before we ship this configuration for Windows DX12 PC platform, we’d like to confirm:

  1. Are these cvars safe to use in a shipped/production build, or are they intended only for debugging/profiling purposes?
  2. Are there any known rendering correctness issues, visual artifacts?
  3. Is there any risk of these settings being deprecated in future engine versions?

Thanks in advance,

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Hi Oleksii,

In general, I don’t see an issue with turning off those cvars if you are seeing better performance on lower-end hardware. Those cvars are meant to help parallelize the recording of GPU commands executed each frame on the CPU side, so it makes sense to keep them off to reduce thread contention on CPUs with low core counts. Since these cvars are mainly concerned with recording the work, there should be no visual artifacts, since what is executed on the GPU will not actually change. There should not be any risk of deprecation either, since we still aim to support lower-end hardware in the future. I hope that clears up your concerns, but please feel free to ask any follow-up questions.

Cheers,

Tim

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