LTX-2.5 distilled LoRA-450 — rank-reduced (ceil72 / ceil128)
Rank-reduced versions of the official
Lightricks/LTX-2.5
loras/ltx-2.5-22b-distilled-lora-450-bf16.safetensors, for few-step
("turbo") sampling on consumer GPUs where the full 8.9 GB rank-450 file
doesn't fit next to the model during inference or training previews.
| File | Size | Rank ceiling | Median kept energy |
|---|
..._fro90_ceil72.safetensors | 1.38 GB | 72 | 0.71 |
..._fro90_ceil128.safetensors | 2.31 GB | 128 | 0.82 |
Start with ceil72 (validated in training previews at weight 0.8 with the
official 8-step sigma schedule); use ceil128 if you want closer fidelity
and have the headroom.
Recipe
Per module, the delta B @ A is truncated by factored SVD (QR of both
factors + core SVD — mathematically optimal rank-k approximation):
singular values kept until 90% Frobenius energy, capped at rank 72,
with a small condition safeguard. Same key format as the original
(diffusion_model.*.lora_A/lora_B), drop-in wherever the original loads.
Honest quality numbers
The rank-450 distillation delta is genuinely high-rank; the ceiling binds
for most modules. Per-module retained Frobenius energy (1,660 modules):
| ceil72 | ceil128 |
|---|
| ceiling-capped | 74% | 63% |
| median kept energy | 0.71 | 0.82 |
| 5th percentile | 0.46 | 0.61 |
| worst module | 0.38 | 0.54 |
Full per-module breakdowns in the reduce_report_*.json files. Despite the
haircut, distillation behavior is redundant across directions in practice —
the ceil72 file renders clean 8-step previews. A spectral check against the
official distilled transformer confirms the rank-450 LoRA is the exact
source of that checkpoint (the delta spectrum cliffs at rank 450), so SVD
truncation of this LoRA is the optimal reduction — there is no extra signal
to extract from the full model. If you need maximum fidelity, use the
official full-rank file. Typical usage: weight ~0.8 with the official
8-step sigma schedule.
Provenance
Derivative of the official Lightricks release; the
LTX-2.x Community License
applies. Produced with
ltx2_reduce_lora.py (musubi-tuner LTX-2 branch).