stable-diffusion.cpp/docs/caching.md

Caching

Caching methods accelerate diffusion inference by reusing intermediate computations when changes between steps are small.

Cache Modes

Mode	Target	Description
ucache	UNET models	Condition-level caching with error tracking
easycache	DiT models	Condition-level cache
dbcache	DiT models	Block-level L1 residual threshold
taylorseer	DiT models	Taylor series approximation
cache-dit	DiT models	Combined DBCache + TaylorSeer

UCache (UNET Models)

UCache caches the residual difference (output - input) and reuses it when input changes are below threshold.

sd-cli -m model.safetensors -p "a cat" --cache-mode ucache --cache-option "threshold=1.5"

Parameters

Parameter	Description	Default
threshold	Error threshold for reuse decision	1.0
start	Start caching at this percent of steps	0.15
end	Stop caching at this percent of steps	0.95
decay	Error decay rate (0-1)	1.0
relative	Scale threshold by output norm (0/1)	1
reset	Reset error after computing (0/1)	1

Reset Parameter

The reset parameter controls error accumulation behavior:

• reset=1 (default): Resets accumulated error after each computed step. More aggressive caching, works well with most samplers.
• reset=0: Keeps error accumulated. More conservative, recommended for euler_a sampler.

EasyCache (DiT Models)

Condition-level caching for DiT models. Caches and reuses outputs when input changes are below threshold.

--cache-mode easycache --cache-option "threshold=0.3"

Parameters

Parameter	Description	Default
threshold	Input change threshold for reuse	0.2
start	Start caching at this percent of steps	0.15
end	Stop caching at this percent of steps	0.95

Cache-DIT (DiT Models)

For DiT models like FLUX and QWEN, use block-level caching modes.

DBCache

Caches blocks based on L1 residual difference threshold:

--cache-mode dbcache --cache-option "threshold=0.25,warmup=4"

TaylorSeer

Uses Taylor series approximation to predict block outputs:

--cache-mode taylorseer

Cache-DIT (Combined)

Combines DBCache and TaylorSeer:

--cache-mode cache-dit --cache-preset fast

Parameters

Parameter	Description	Default
Fn	Front blocks to always compute	8
Bn	Back blocks to always compute	0
threshold	L1 residual difference threshold	0.08
warmup	Steps before caching starts	8

Presets

Available presets: slow, medium, fast, ultra (or s, m, f, u).

--cache-mode cache-dit --cache-preset fast

SCM Options

Steps Computation Mask controls which steps can be cached:

--scm-mask "1,1,1,1,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,1"

Mask values: 1 = compute, 0 = can cache.

Policy	Description
dynamic	Check threshold before caching
static	Always cache on cacheable steps

--scm-policy dynamic

Performance Tips

• Start with default thresholds and adjust based on output quality
• Lower threshold = better quality, less speedup
• Higher threshold = more speedup, potential quality loss
• More steps generally means more caching opportunities