Black Forest Labs designed these models for opposite ends of the image generation spectrum. Flux 1 Schnell (German for "fast") is the speed-optimized workhorse of the Flux family, generating 1-megapixel images in about a second. Flux 1.1 Pro Ultra is the company's premium resolution champion, producing 4-megapixel images with native support for outputs up to 2048x2048 pixels and beyond.
The numbers define an extreme gap: Schnell finishes in roughly 1 second at minimal cost. Pro Ultra takes approximately 8 seconds and costs 18x more—a significant price difference with an 8x speed penalty. But Pro Ultra generates images with 4x the pixel count, which fundamentally changes what's possible in the final output.
Pro Ultra's "raw mode" is particularly notable. When enabled (it's on by default), the model produces images with more natural, less processed aesthetics—closer to what you'd expect from a DSLR camera than AI generation. This makes Pro Ultra especially compelling for professional photography applications where that authentic look matters.
These models don't compete directly—they serve different purposes. The question is whether your use case demands resolution and photorealism, or whether speed and cost efficiency take priority.
Note: Flux 1.1 Pro Ultra outputs 4-megapixel images natively. When you need print-ready resolution or large-format display, this eliminates the need for AI upscaling workflows entirely.