Can the RTX 4090 24 GB run LTX-Video 13B (0.9.8)?
Yes. FP8 fits on the RTX 4090 24 GB with 4.0 GB to spare.
Take FP8 (15.7 GB). In use it comes to about 20.0 GB, with 4.0 GB left over on 24 GB.
01What to download
| Part | File | Folder | Size | |
|---|---|---|---|---|
| Model | ltxv-13b-0.9.8-dev-fp8.safetensors FP8 · Lightricks/LTX-Video | models/diffusion_models | 15.7 GB | Download → |
| Text encoder | t5xxl_fp8_e4m3fn_scaled.safetensors T5-XXL FP8 (scaled) · comfyanonymous/flux_text_encoders | models/text_encoders | 5.2 GB | Download → |
| Total download · keep about the same free on disk | 20.9 GB | |||
Alternatives: T5-XXL FP16 (9.8 GB). Sizes from Hugging Face, 2026-10-01.
02Every LTX-Video 13B file on 24 GB
| File | Size | Needed | On this card | Quality | Download |
|---|---|---|---|---|---|
| 16-bit SAFETENSORS · Lightricks | 28.6 GB | 32.9 GB | 8.9 GB too big | the original weights | Hugging Face → |
| FP8 ← SAFETENSORS · Lightricks | 15.7 GB | 20.0 GB | fits · 4.0 GB spare | practically identical to the original | Hugging Face → |
| Q8_0 GGUF · QuantStack | 14.0 GB | 18.3 GB | fits · 5.7 GB spare | practically identical to the original | Hugging Face → |
| Q6_K GGUF · QuantStack | 10.9 GB | 15.2 GB | fits · 8.8 GB spare | very close to the original | Hugging Face → |
| Q5_K_M GGUF · QuantStack | 9.8 GB | 14.1 GB | fits · 9.9 GB spare | close; small differences in fine detail | Hugging Face → |
| Q4_K_M GGUF · QuantStack | 8.8 GB | 13.1 GB | fits · 10.9 GB spare | good; some loss in fine detail and text | Hugging Face → |
| Q3_K_M GGUF · QuantStack | 6.5 GB | 10.8 GB | fits · 13.2 GB spare | noticeable loss of detail | Hugging Face → |
| Q2_K GGUF · QuantStack | 4.7 GB | 9.0 GB | fits · 15.0 GB spare | heavy loss; a last resort | Hugging Face → |
“Needed” adds 3.5 GB of working memory for LTX-Video 13B and a 0.8 GB reserve. Sizes 2026-10-01.
03Measured and reported results
Nobody has sent measured numbers for this pair yet. If you run LTX-Video 13B on a RTX 4090 24 GB, send your time per image and peak VRAM and it will appear here, credited.
04About the RTX 4090 24 GB
The RTX 4090 24 GB is an Ada Lovelace GPU with hardware FP8, so ComfyUI can compute Comfy-Org's FP8 files natively: small and fast. (Plain FP8 files use FP8 maths with the --fast fp8_matrix_mult option.)
24 GB GDDR6X · 384-bit · 1008 GB/s · Ada Lovelace. Everything that runs on it →
05Questions
How much VRAM does LTX-Video 13B need?
Around 9.0 GB with the smallest file (Q2_K) and 20.0 GB with an 8-bit file (FP8). The full 16-bit file needs about 32.9 GB.
Which LTX-Video 13B file should I download for the RTX 4090 24 GB?
FP8 (15.7 GB) from Lightricks/LTX-Video.
FP8 or Q8_0 for LTX-Video 13B on the RTX 4090 24 GB?
FP8 (15.7 GB): the RTX 4090 24 GB computes it natively, while Q8_0 (14.0 GB) is unpacked on the fly.
How much do I need to download for LTX-Video 13B on the RTX 4090 24 GB?
20.9 GB: ltxv-13b-0.9.8-dev-fp8.safetensors, t5xxl_fp8_e4m3fn_scaled.safetensors.