FLUX.2 Klein 9B Previewvs.SANA-1.5 4.8B 1024px

Which one is better?

In our own test, FLUX.2 Klein 9B Preview leads. Neither is in the arena. Neither has an API price.

Test images

Same task, the first image of each. The task with the biggest difference is preselected.

FLUX.2 Klein 9B Preview: Product photography, first image from the fixed test run — FLUX.2 Klein 9B Preview73 out of 100

SANA-1.5 4.8B 1024px: Product photography, first image from the fixed test run — SANA-1.5 4.8B 1024px1 out of 100

Result for “Product photography”:FLUX.2 Klein 9B Preview ahead

Prompt given to both modelsCreate a square premium product photograph of a brushed titanium wristwatch standing upright on dark green marble. The watch has a cream dial, thin black hands set to 10:10, twelve distinct hour markers, a realistic crown, and a dark brown leather strap. Soft window light from the left, controlled reflections, shallow depth of field, no text, no logo, no extra objects.

What the rating looks at: Materials, reflections, and fine details.

“Ahead”: better in all three rating rounds. “Slightly ahead”: a higher value, but not in every round.

Test protocol of the images

Each test attempt uses the same archived prompt and one request. The first output of that attempt counts. Repeats after technical test failures are disclosed for the affected images. Files are normalized to 1,024 × 1,024 pixels without cropping. Provider resolution, randomness, quality tier and prompt processing can still differ. The images are a practical visual test, not a reconstruction of the arena configuration.

Character and detail

FLUX.2 Klein 9B Preview: manual, BFL API /v1/flux-2-klein-9b-preview (distinct preview checkpoint); native 1024x1024, 1:1; one request, first output; seed=3453819885; output_format=png; no reference images or negative prompt, generated Nov 2, 2026, 7:05 PM. Source

SANA-1.5 4.8B 1024px: manual, local PyTorch 2.13.0, Diffusers 0.36.0; Efficient-Large-Model/SANA1.5_4.8B_1024px_diffusers@9468102c3cebb657f8c4b5f1e5a71e989a15f10d; native 1024x1024, 1:1; one request, first output; steps=20, guidance=4.5, seed=6914427587596023045; mps for text encoder and denoising; cpu for native VAE decode; bfloat16 for text encoder and transformer; float32 for VAE; native prompt preprocessing lowercases input; optional instruction disabled, generated Nov 2, 2026, 5:42 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: 985a75b38642a9f0e5e0c0e0c67f1b7f67780d42bd2168fa24e9a7a7a94b0da6

FLUX.2 Klein 9B Preview image SHA 256: 83bd206858a0d2bfab8a9d3bb7d90de6ff568017464a8168726175a6b324a90c

SANA-1.5 4.8B 1024px image SHA 256: 97badf740db81367de7d6af73cc9313f1dfc4fe8383183ddbd9fc12cc67b35ee

Infographic

FLUX.2 Klein 9B Preview: manual, BFL API /v1/flux-2-klein-9b-preview (distinct preview checkpoint); native 1024x1024, 1:1; one request, first output; seed=1679342581; output_format=png; no reference images or negative prompt, generated Nov 2, 2026, 7:06 PM. Source

SANA-1.5 4.8B 1024px: manual, local PyTorch 2.13.0, Diffusers 0.36.0; Efficient-Large-Model/SANA1.5_4.8B_1024px_diffusers@9468102c3cebb657f8c4b5f1e5a71e989a15f10d; native 1024x1024, 1:1; one request, first output; steps=20, guidance=4.5, seed=3447101042619426797; mps for text encoder and denoising; cpu for native VAE decode; bfloat16 for text encoder and transformer; float32 for VAE; native prompt preprocessing lowercases input; optional instruction disabled, generated Nov 2, 2026, 5:43 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: ed65cb4e6a51e2336f8b149ad4cbb16e020f07d527ad94362e719d2dcf91d94f

FLUX.2 Klein 9B Preview image SHA 256: deb8da580546e3d22e20222c5c7e8c1a95197f27be4bff0b064eba603bda7b47

SANA-1.5 4.8B 1024px image SHA 256: 6c23b2df82d085e155c012c16915d04dd3a1aacdb78c9604eb74668309e07b38

Product photography

FLUX.2 Klein 9B Preview: manual, BFL API /v1/flux-2-klein-9b-preview (distinct preview checkpoint); native 1024x1024, 1:1; one request, first output; seed=132780547; output_format=png; no reference images or negative prompt; first provider output recovered by GET after local regional API validation stopped polling; no regeneration, generated Nov 2, 2026, 7:04 PM. Source

SANA-1.5 4.8B 1024px: manual, local PyTorch 2.13.0, Diffusers 0.36.0; Efficient-Large-Model/SANA1.5_4.8B_1024px_diffusers@9468102c3cebb657f8c4b5f1e5a71e989a15f10d; native 1024x1024, 1:1; one request, first output; steps=20, guidance=4.5, seed=1122699157863902383; mps for text encoder and denoising; cpu for native VAE decode; bfloat16 for text encoder and transformer; float32 for VAE; native prompt preprocessing lowercases input; optional instruction disabled, generated Nov 2, 2026, 5:41 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: c67fd71e91304458a2feef5c91efa8677260fab0c0099a29a2c52cb579f5b2f3

FLUX.2 Klein 9B Preview image SHA 256: b1f17cd46fcd8f8b862da7c59900c1616ac3db8052d92a344720b7dc7fcb75ea

SANA-1.5 4.8B 1024px image SHA 256: 0ceaa96a83bc85d12c7f56b925226a346ee9b42f831fa5a9592edc4fc1e7ce81

Typography and layout

FLUX.2 Klein 9B Preview: manual, BFL API /v1/flux-2-klein-9b-preview (distinct preview checkpoint); native 1024x1024, 1:1; one request per attempt; two submissions; original signed output expired after local retrieval failure; first output of technical repeat with unchanged prompt and seed; seed=4230828387; output_format=png; no reference images or negative prompt, generated Nov 2, 2026, 7:06 PM. Source

SANA-1.5 4.8B 1024px: manual, local PyTorch 2.13.0, Diffusers 0.36.0; Efficient-Large-Model/SANA1.5_4.8B_1024px_diffusers@9468102c3cebb657f8c4b5f1e5a71e989a15f10d; native 1024x1024, 1:1; one request, first output; steps=20, guidance=4.5, seed=623973358981804157; mps for text encoder and denoising; cpu for native VAE decode; bfloat16 for text encoder and transformer; float32 for VAE; native prompt preprocessing lowercases input; optional instruction disabled, generated Nov 2, 2026, 5:40 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: 2e012c3d14ee5dd02203a94f394ca80a5038cdebd6032b25a8b8a221f2255419

FLUX.2 Klein 9B Preview image SHA 256: 6cc5a70118def87bf0ec737b20c9dd56c3a7dd3ec776e007b8a5fdadd4c27849

SANA-1.5 4.8B 1024px image SHA 256: 8371e0e35ad4472b71165cedd1940eb0339b19c24f801c3b956874c090a327fc

The numbers at a glance

Arena ratingfrom votes by users · higher is better

n/a

FLUX.2 Klein 9B Preview

not in the arena

n/a

SANA-1.5 4.8B 1024px

not in the arena

GraduallyBenchour own rating, 0 to 100 · higher is better

FLUX.2 Klein 9B Preview

Rank 48 of 108

SANA-1.5 4.8B 1024px

Rank 106 of 108

Price per imagedollars through the API · lower is better

n/a

FLUX.2 Klein 9B Preview

no API price

n/a

SANA-1.5 4.8B 1024px

no API price

Ranks among the 21 image models with an arena rating and the 108 with a GraduallyBench run; prices compared with 28 models with an API price.

FLUX.2 Klein 9B Preview

Subscription: n/a No plan in Germany names exactly this model.
Via API: No API price known. Access: API.
Weights: unknown.

SANA-1.5 4.8B 1024px

Subscription: n/a No plan in Germany names exactly this model.
Via API: No API price known. Access: local.
License: Open weights.

Subscriptions only count plans that name exactly this model. Subscription prices include VAT, API prices are in dollars.

GraduallyBench from Nov 3, 2026 · Subscription database from Sep 29, 2026 (38 days old)

All data side by side

The better value is bold. For ratings only when the gap is clear.

Kennzahl	FLUX.2 Klein 9B Preview	SANA-1.5 4.8B 1024px
Ratings
Arena ratingfrom votes by users, higher is better	n/a	n/a
Arena rank	n/a	n/a
Arena votesmore votes, a safer rating	n/a	n/a
GraduallyBenchour own rating, 0 to 100	62	4
GraduallyBench by task
Typography and layoutLegible text, hierarchy, and composition	56	8
Product photographyMaterials, reflections, and fine details	73	1
Character and detailAnatomy, clothing, and spatial consistency	45	0
InfographicNumbers, labels, and visual organization	75	6
API price
Per imagelower is better	n/a	n/a
100 images	n/a	n/a
Profile
Released	n/a	Mar 16, 2025
Weightsopen means: runs locally	unknown	open
Lifecycle	Preview API route with newer quality/speed improvements; the stable 9B route remains separate	no notice
Access	API	local
Parameters	9 billion	4.8 billion
Largest output	not consistently published	not consistently published
Plans in Germanynaming exactly this model	n/a	n/a

API prices for one image at 1,024 × 1,024 pixels according to Artificial Analysis.

Sources: FLUX.2 Klein 9B Preview model source, status source (verified Nov 1, 2026) · SANA-1.5 4.8B 1024px model source (verified Nov 1, 2026)

Arena ratings by category

From blind votes on LMArena. “Ahead” means the lead is clear.

No shared arena score in the stored snapshot

The stored benchmark database contains no measurement for FLUX.2 Klein 9B Preview and SANA-1.5 4.8B 1024px from the same arena and category. Older model versions are not used as substitutes.

More comparisons

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