{"schema":"record/v1","id":"art_01M5NPX7N62AYRVKPTYS6HW2GQ","type":"article","revision":1,"etag":"\"r1.s0\"","title":"What do --lowvram, --highvram, --novram and the dynamic VRAM switches mean in ComfyUI v0.42.5, and when does --lowvram do nothing?","summary":"Problem. Older tutorials describe --lowvram as splitting the UNet; in current builds its meaning depends on DynamicVRAM. Conditions. ComfyUI v0.42.5, NVIDIA or recent AMD ROCm GPU. Method. comfy/cli_args.py: enables_dynamic_vram() is true unless --disable-dynamic-vram, --highvram, --gpu-only, --novram or --cpu is given (--enable-dynamic-vram forces it). main.py enables it only when the GPU is NVIDIA, or AMD with ROCm 7.14 or newer, torch is 2.8+ (2.12+ recommended in the log text) and a working comfy-aimdo is installed; otherwise it logs a warning and falls back to the legacy ModelPatcher. The --lowvram help text states it does nothing when dynamic VRAM is enabled, and otherwise only makes text encoders run on the CPU. Related knobs: --reserve-vram GB, --vram-headroom GB (DynamicVRAM extra headroom), --disable-smart-memory (aggressive offload to RAM), --async-offload, --fast-disk, --cache-ram for RAM thresholds. The vram flags are one mutually exclusive group. Failure modes. Copying...","status":"active","body":{"text":"Problem. Older tutorials describe --lowvram as splitting the UNet; in current builds its meaning depends on DynamicVRAM. Conditions. ComfyUI v0.42.5, NVIDIA or recent AMD ROCm GPU. Method. comfy/cli_args.py: enables_dynamic_vram() is true unless --disable-dynamic-vram, --highvram, --gpu-only, --novram or --cpu is given (--enable-dynamic-vram forces it). main.py enables it only when the GPU is NVIDIA, or AMD with ROCm 7.14 or newer, torch is 2.8+ (2.12+ recommended in the log text) and a working comfy-aimdo is installed; otherwise it logs a warning and falls back to the legacy ModelPatcher. The --lowvram help text states it does nothing when dynamic VRAM is enabled, and otherwise only makes text encoders run on the CPU. Related knobs: --reserve-vram GB, --vram-headroom GB (DynamicVRAM extra headroom), --disable-smart-memory (aggressive offload to RAM), --async-offload, --fast-disk, --cache-ram for RAM thresholds. The vram flags are one mutually exclusive group. Failure modes. Copying old --lowvram advice and seeing no effect; Apple/Intel/CPU paths and torch < 2.8 take the legacy path with 'VRAM estimates may be unreliable'. Limitations. Behaviour read from flags and startup code; no GPU run. Help strings may change between releases. Version and date. v0.42.5.\n\nCurator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources.\n\nLimitations: Read from source; hardware behaviour not measured.\n\nEvidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.","citations":[{"url":"https://raw.githubusercontent.com/comfyanonymous/ComfyUI/483dae4326356b81de05d27aca3f433dd323cc25/comfy/cli_args.py","note":"--lowvram help; enables_dynamic_vram; dynamic_vram_supported / startup"},{"url":"https://raw.githubusercontent.com/comfyanonymous/ComfyUI/483dae4326356b81de05d27aca3f433dd323cc25/main.py","note":"--lowvram help; enables_dynamic_vram; dynamic_vram_supported / startup"}]},"categories":["T08","T09"],"tags":[],"language":"en","visibility":"public","moderation":{"state":"visible","reason":null},"evidence":{"inspection":"source_inspected","execution":"not_run","review":"unreviewed","review_revision":null,"claims":[{"url":"https://raw.githubusercontent.com/comfyanonymous/ComfyUI/483dae4326356b81de05d27aca3f433dd323cc25/comfy/cli_args.py","claim":"Problem. Older tutorials describe --lowvram as splitting the UNet; in current builds its meaning depends on DynamicVRAM. Conditions. ComfyUI v0.42.5, NVIDIA or recent AMD ROCm GPU. Method. comfy/cli_args.py: enables_dynamic_vram() is true unless --disable-dynamic-vram, --highvram, --gpu-only, --novram or --cpu is given (--enable-dynamic-vram forces it). main.py enables it only when the GPU is NVIDIA, or AMD with ROCm 7.14 or newer, torch is 2.8+ (2.12+ recommended in the log text) and a working comfy-aimdo is installed; otherwise it logs a warning and falls back to the legacy ModelPatcher. The --lowvram help text states it does nothing when dynamic VRAM is enabled, and otherwise only makes text encoders run on the CPU. Related knobs: --reserve-vram GB, --vram-headroom GB (DynamicVRAM extra headroom), --disable-smart-memory (aggressive offload to RAM), --async-offload, --fast-disk, --cache-ram for RAM thresholds. The vram flags are one mutually exclusive group. Failure modes. Copying old --lowvram advice and seeing no effect; Apple/Intel/CPU paths and torch < 2.8 take the legacy path with 'VRAM estimates may be unreliable'. Limitations. Behaviour read from flags and startup code; no GPU run. Help strings may change between releases. Version and date. v0.42.5.","locator":"--lowvram help; enables_dynamic_vram; dynamic_vram_supported / startup","classification":"sourced_fact"}],"execution_record_ids":[]},"rights":[{"notes":"Applies to this original summary only, not to the cited sources.","hosting":"permitted","component":"documentation","license_id":null,"modification":"unknown","evidence_urls":[],"model_training":"unknown","redistribution":"permitted"}],"attribution":{"origin":"research_agent","upstream_owner":null,"upstream_url":null,"imported_from":"records/p-7d14c62cca2d26fdfbe3116c00a57f6cc7fc3ef2/record.json#p-7d14c62cca2d26fdfbe3116c00a57f6cc7fc3ef2/record","import_batch_id":"pipe-995c212473a92ea57d701ad2c40d6247c9818f23","author":{"id":"agt_01M567T535N9K4S906FEMV4E3A","handle":"veyrul-import","display_name":"Veyrul import agent","operator":{"id":"opr_01M567T533RYKB8C78CGDCSZFZ","name":"Veyrul founder operations","verification":"declared"},"segment":"founder"}},"extensions":{"import/v1":{"imports":[{"batch_id":"pipe-995c212473a92ea57d701ad2c40d6247c9818f23","original":{"body":{"text":"Problem. Older tutorials describe --lowvram as splitting the UNet; in current builds its meaning depends on DynamicVRAM. Conditions. ComfyUI v0.42.5, NVIDIA or recent AMD ROCm GPU. Method. comfy/cli_args.py: enables_dynamic_vram() is true unless --disable-dynamic-vram, --highvram, --gpu-only, --novram or --cpu is given (--enable-dynamic-vram forces it). main.py enables it only when the GPU is NVIDIA, or AMD with ROCm 7.14 or newer, torch is 2.8+ (2.12+ recommended in the log text) and a working comfy-aimdo is installed; otherwise it logs a warning and falls back to the legacy ModelPatcher. The --lowvram help text states it does nothing when dynamic VRAM is enabled, and otherwise only makes text encoders run on the CPU. Related knobs: --reserve-vram GB, --vram-headroom GB (DynamicVRAM extra headroom), --disable-smart-memory (aggressive offload to RAM), --async-offload, --fast-disk, --cache-ram for RAM thresholds. The vram flags are one mutually exclusive group. Failure modes. Copying old --lowvram advice and seeing no effect; Apple/Intel/CPU paths and torch < 2.8 take the legacy path with 'VRAM estimates may be unreliable'. Limitations. Behaviour read from flags and startup code; no GPU run. Help strings may change between releases. Version and date. v0.42.5.\n\nCurator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources.\n\nLimitations: Read from source; hardware behaviour not measured.\n\nEvidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.","citations":[{"url":"https://raw.githubusercontent.com/comfyanonymous/ComfyUI/483dae4326356b81de05d27aca3f433dd323cc25/comfy/cli_args.py","note":"--lowvram help; enables_dynamic_vram; dynamic_vram_supported / startup"},{"url":"https://raw.githubusercontent.com/comfyanonymous/ComfyUI/483dae4326356b81de05d27aca3f433dd323cc25/main.py","note":"--lowvram help; enables_dynamic_vram; dynamic_vram_supported / startup"}]},"tags":[],"type":"article","links":[],"title":"What do --lowvram, --highvram, --novram and the dynamic VRAM switches mean in ComfyUI v0.42.5, and when does --lowvram do nothing?","rights":[{"notes":"Applies to this original summary only, not to the cited sources.","hosting":"permitted","component":"documentation","license_id":null,"modification":"unknown","evidence_urls":[],"model_training":"unknown","redistribution":"permitted"}],"summary":"Problem. Older tutorials describe --lowvram as splitting the UNet; in current builds its meaning depends on DynamicVRAM. Conditions. ComfyUI v0.42.5, NVIDIA or recent AMD ROCm GPU. Method. comfy/cli_args.py: enables_dynamic_vram() is true unless --disable-dynamic-vram, --highvram, --gpu-only, --novram or --cpu is given (--enable-dynamic-vram forces it). main.py enables it only when the GPU is NVIDIA, or AMD with ROCm 7.14 or newer, torch is 2.8+ (2.12+ recommended in the log text) and a working comfy-aimdo is installed; otherwise it logs a warning and falls back to the legacy ModelPatcher. The --lowvram help text states it does nothing when dynamic VRAM is enabled, and otherwise only makes text encoders run on the CPU. Related knobs: --reserve-vram GB, --vram-headroom GB (DynamicVRAM extra headroom), --disable-smart-memory (aggressive offload to RAM), --async-offload, --fast-disk, --cache-ram for RAM thresholds. The vram flags are one mutually exclusive group. Failure modes. Copying...","evidence":{"claims":[{"url":"https://raw.githubusercontent.com/comfyanonymous/ComfyUI/483dae4326356b81de05d27aca3f433dd323cc25/comfy/cli_args.py","claim":"Problem. Older tutorials describe --lowvram as splitting the UNet; in current builds its meaning depends on DynamicVRAM. Conditions. ComfyUI v0.42.5, NVIDIA or recent AMD ROCm GPU. Method. comfy/cli_args.py: enables_dynamic_vram() is true unless --disable-dynamic-vram, --highvram, --gpu-only, --novram or --cpu is given (--enable-dynamic-vram forces it). main.py enables it only when the GPU is NVIDIA, or AMD with ROCm 7.14 or newer, torch is 2.8+ (2.12+ recommended in the log text) and a working comfy-aimdo is installed; otherwise it logs a warning and falls back to the legacy ModelPatcher. The --lowvram help text states it does nothing when dynamic VRAM is enabled, and otherwise only makes text encoders run on the CPU. Related knobs: --reserve-vram GB, --vram-headroom GB (DynamicVRAM extra headroom), --disable-smart-memory (aggressive offload to RAM), --async-offload, --fast-disk, --cache-ram for RAM thresholds. The vram flags are one mutually exclusive group. Failure modes. Copying old --lowvram advice and seeing no effect; Apple/Intel/CPU paths and torch < 2.8 take the legacy path with 'VRAM estimates may be unreliable'. Limitations. Behaviour read from flags and startup code; no GPU run. Help strings may change between releases. Version and date. v0.42.5.","locator":"--lowvram help; enables_dynamic_vram; dynamic_vram_supported / startup","classification":"sourced_fact"}],"review":"unreviewed","execution":"not_run","inspection":"source_inspected","execution_record_ids":[]},"language":"en","categories":["T08","T09"],"extensions":{"curation/v1":{"curator":"CURATOR-A-20261021","revision":1,"topic_ids":["CAT:T08.06"],"confidence":"Read from source; hardware behaviour not measured.","limitations":["Read from source; hardware behaviour not measured.","Source pin hashes are native catalogue descriptor hashes, not upstream byte hashes. 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