Sampler and sampler names

The node that turns noise into a picture step by step, and what the names in its sampler_name list mean in practice.

In plain words

Generation starts from pure noise. At each step the model looks at the noisy latent and predicts what noise is in it; the sampler removes part of that noise and moves on. After the last step a clean latent remains, and VAE Decode turns it into a picture.

The sampler node is where everything meets: the model, the positive and negative conditioning, the starting latent and the settings. The sampling algorithm (sampler_name) is the rule for how each step moves; the scheduler decides how big each step is.

<!-- diagram: five small squares from left to right, from pure noise to a clear picture of a lake, labelled step 0, 5, 10, 15, 20 -->

Where you meet it in a graph

  • KSampler: inputs model, positive, negative, latent_image; fields seed, control_after_generate, steps, cfg, sampler_name, scheduler, denoise; output LATENT.
  • KSampler (Advanced): adds add_noise, start_at_step, end_at_step, return_with_leftover_noise, to split one generation between two samplers (base and refiner, or the two Wan 2.2 models).
  • SamplerCustom and SamplerCustomAdvanced: assembled from parts: NOISE (RandomNoise), GUIDER (CFGGuider, BasicGuider), SAMPLER (KSamplerSelect), SIGMAS (BasicScheduler and others). Flux and many newer templates use this form.
  • Packs have their own samplers (for example WanVideo Sampler).

Sampler names in practice

NameWhat people use it for
eulerSimple and dependable. The default in many Flux, Wan, Qwen-Image and Z-Image templates. A good first choice.
euler_ancestral (_a)Adds fresh noise every step: more variety, softer look; the picture keeps changing as you change steps.
dpmpp_2mPopular with SDXL and SD 1.5, usually with the karras scheduler; sharp at 20 to 30 steps.
dpmpp_2m_sde, dpmpp_sde, dpmpp_3m_sdeStochastic: more fine detail and variation; slower per step.
uni_pc, uni_pc_bh2Converge in few steps; used in some video graphs.
ddimThe classic; mostly for old graphs.
lcmOnly for LCM models and LCM LoRAs, at 4 to 8 steps and cfg about 1 to 2.
res_multistep, er_sde, gradient_estimation and othersNewer methods; use them when a template or model page names them.

Names ending in _ancestral or _sde add noise during sampling, so the same seed gives slightly different results with different step counts. Names ending in _gpu do the same work with noise made on the graphics card.

Typical mistakes

  • Changing sampler and scheduler at random: on a well-trained model the difference is small next to the prompt and the seed. Start from the model's page.
  • An ancestral sampler when comparing settings: results jump. Use euler for comparisons.
  • lcm on an ordinary model: a blurry, unfinished picture.

How the app helps

The node description of every sampler explains its inputs. The lessons The sampler's settings and Choosing a sampler and a scheduler go through its fields; in KSampler (Advanced) graphs the video lessons check that the two samplers hand over at the same step. In Properties, a field with a built-in note has a button What this field does next to its name; it opens the note under the field: what the field does and what to put in it.

See also

This page is imported from the application repository's wiki (docs/wiki/concepts/Sampler.md, revision b8e3f71). The same guide is built into the app: Help ▸ User guide.

To refresh it, run npm run import and then npm run build in the website folder.