ZMIME
Comparison · 2 models · Updated Oct 4, 2026

GPT-5.3 Chat vs MiMo-V2.6-Pro-UltraSpeed

MiMo-V2.6-Pro-UltraSpeed comes out ahead, 44 to 32 on our weighted score, though GPT-5.3 Chat is 11% cheaper per token.

  1. OpenAI

    GPT-5.3 Chat

    Released Mar 3, 2026Deprecated

    32/100
    • ECI—
    • Price$1.75 / $14.00
    • Context128K
  2. Our pick

    Xiaomi

    MiMo-V2.6-Pro-UltraSpeed

    Released Sep 21, 2026

    44/100
    • ECI—
    • Price$4.35 / $8.70
    • Context1.05M
  3. Add a model

    Make it a three-way comparison.

01 — Verdict

MiMo-V2.6-Pro-UltraSpeed is our pick

MiMo-V2.6-Pro-UltraSpeed is the better all-round choice, scoring 44/100 against GPT-5.3 Chat (32). It leads on inputs & features and context window. GPT-5.3 Chat wins on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

  • CapabilityNot enough dataNo independent benchmark covers every model here yet
  • Lowest priceGPT-5.3 ChatGPT-5.3 Chat $4.81 · MiMo-V2.6-Pro-UltraSpeed $5.44 per 1M tokens (3:1 blend)
  • Longest contextMiMo-V2.6-Pro-UltraSpeedMiMo-V2.6-Pro-UltraSpeed 1,048,576 · GPT-5.3 Chat 128,000 tokens
  • Widest inputsMiMo-V2.6-Pro-UltraSpeedGPT-5.3 Chat: Text, Images · MiMo-V2.6-Pro-UltraSpeed: Text, Images, Audio, Video
  • Self-hostingMiMo-V2.6-Pro-UltraSpeedPublishes downloadable weights
How the score is built
MeasureWeightGPT-5.3 ChatMiMo-V2.6-Pro-UltraSpeed
Price50%1815
Inputs & features30%6080
Context window20%2461
Overall100%32/10044/100

Left out because at least one model lacks the data: capability. The remaining weights were rescaled.

02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

GPT-5.3 Chat vs MiMo-V2.6-Pro-UltraSpeed specifications side by side
SpecificationGPT-5.3 ChatOpenAIMiMo-V2.6-Pro-UltraSpeedXiaomi
Capability
Capabilities Index (ECI)——
ECI rank——
Price per million tokens
Input$1.75 (best)$4.35
Output$14.00$8.70 (best)
Cached input$0.175$0.036 (best)
Blended (3:1)$4.81 (best)$5.44
Long-context rateSame rateSame rate
Price sourceOfficial OpenAI APIOfficial Xiaomi API
Limits
Context window128,000 tokens1,048,576 tokens (best)
Max output16,384 tokens131,072 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsNoNo
AudioNoYes
VideoNoYes
ReasoningNoYes
Tool callingYesYes
Structured outputYesNo
Availability
WeightsProprietaryOpen
API model IDgpt-5.3-chat-latestmimo-v2.6-pro-ultraspeed
API providers49 (best)
ReleasedMar 3, 2026Sep 21, 2026
Knowledge cutoffAug 31, 2025—
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • GPT-5.3 Chat$45.50
  • MiMo-V2.6-Pro-UltraSpeed$60.90
04 — Questions

Which should you choose?

Which is better: GPT-5.3 Chat or MiMo-V2.6-Pro-UltraSpeed?

MiMo-V2.6-Pro-UltraSpeed is the better all-round choice, scoring 44/100 against GPT-5.3 Chat (32). It leads on inputs & features and context window. GPT-5.3 Chat wins on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

Which is cheaper, GPT-5.3 Chat or MiMo-V2.6-Pro-UltraSpeed?

GPT-5.3 Chat is cheaper at $1.75 input / $14.00 output per million tokens (official OpenAI API price). MiMo-V2.6-Pro-UltraSpeed costs $4.35 input / $8.70 output per million tokens (official Xiaomi API price). At a typical mix of three input tokens to one output token, that is $4.81 per million tokens for GPT-5.3 Chat versus $5.44 for MiMo-V2.6-Pro-UltraSpeed (1.1× as much).

Which scores higher on benchmarks?

There is no independent benchmark that covers both models yet. GPT-5.3 Chat has not been scored yet and MiMo-V2.6-Pro-UltraSpeed has not been scored yet.

Which is better for coding?

There are no published SWE-bench Verified results for GPT-5.3 Chat and MiMo-V2.6-Pro-UltraSpeed yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.

Which has the bigger context window?

MiMo-V2.6-Pro-UltraSpeed has the largest context window at 1,048,576 tokens, against 128,000 for GPT-5.3 Chat. Maximum output per response: GPT-5.3 Chat up to 16,384, MiMo-V2.6-Pro-UltraSpeed up to 131,072 tokens.

Which can read images, PDFs, audio or video?

GPT-5.3 Chat accepts text and images; MiMo-V2.6-Pro-UltraSpeed accepts text, images, audio and video. MiMo-V2.6-Pro-UltraSpeed handles the widest range of inputs.

Are any of these open source?

MiMo-V2.6-Pro-UltraSpeed publishes its weights and can be self-hosted; GPT-5.3 Chat is proprietary.

Which is newer?

MiMo-V2.6-Pro-UltraSpeed is the newest, released Sep 21, 2026. GPT-5.3 Chat came out Mar 3, 2026. Knowledge cutoff: GPT-5.3 Chat Aug 31, 2025.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.