Question 1

What does this Step 3.5 Flash vs MiMo-V2.5-Pro-UltraSpeed comparison cover?

Accepted Answer

It brings together documented inputs and outputs, token limits, deployment terms and available pricing. When both models have source-linked, verified results on a shared benchmark, those results are shown with their individual sources. The comparison is a starting point for evaluating your own workload.

Question 2

Which is cheaper: Step 3.5 Flash or MiMo-V2.5-Pro-UltraSpeed?

Accepted Answer

Step 3.5 Flash lists $0.10 input and $0.30 output per 1M tokens. MiMo-V2.5-Pro-UltraSpeed lists $1.305 input and $2.61 output. The cheaper workload depends on the mix of input and output. Long-context tiers, caching, batch processing and retries can change the bill.

Question 3

Which has the larger context window: Step 3.5 Flash or MiMo-V2.5-Pro-UltraSpeed?

Accepted Answer

Step 3.5 Flash lists 256K tokens and MiMo-V2.5-Pro-UltraSpeed lists 1.05M. MiMo-V2.5-Pro-UltraSpeed therefore has the larger recorded context window, but capacity alone is not a quality score.

Question 4

Which is faster: Step 3.5 Flash or MiMo-V2.5-Pro-UltraSpeed?

Accepted Answer

There is no matched speed measurement for both models with the same source, host, region and date. Test the same prompts at your expected concurrency and measure time to the first useful response as well as complete task time.

Question 5

What input and output types do Step 3.5 Flash and MiMo-V2.5-Pro-UltraSpeed support?

Accepted Answer

Step 3.5 Flash records text input and text output. MiMo-V2.5-Pro-UltraSpeed records text input and text output. “Not documented” means the current source record is incomplete; it does not prove that a modality is unsupported.

Question 6

Should I choose Step 3.5 Flash or MiMo-V2.5-Pro-UltraSpeed?

Accepted Answer

Consider Step 3.5 Flash if you need larger maximum output or a lower listed input rate or a lower listed output rate. Consider MiMo-V2.5-Pro-UltraSpeed if you need larger context. Test both on the same representative examples and judge the output against your acceptance criteria. Include tool failures, retries and the time to a completed task.

Specification	Step 3.5 Flash	MiMo-V2.5-Pro-UltraSpeed
Provider	StepFun	Xiaomi
Listed pricing route	StepFun	Xiaomi
Model family	—	mimo
Accepted inputs	text	text
Produced outputs	text	text
Context window	256K	1.05MHigher
Max output	256KHigher	131.07K
Input price / 1M	$0.10Lower	$1.305
Output price / 1M	$0.30Lower	$2.61
Reasoning mode	Documented	Documented
Tool calling	Documented	Documented
Image input	Not documented	Not documented
Audio input	Not documented	Not documented
Structured output	Not documented	Not documented
License	Open weights	Open weights

Step 3.5 Flash vs MiMo-V2.5-Pro-UltraSpeed

Step 3.5 Flash

MiMo-V2.5-Pro-UltraSpeed

Key differences

Pricing, limits and capabilities

Which model should you choose?

Documentation and model profiles

Questions people ask

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