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BenchLM

Mistral Medium 3.5 128B vs o1-preview

Updated September 29, 2026. Rank cannot separate these two. Price, access, and your workload decide. Public scores include evidence status and uncertainty.

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Decision reading

The public evidence has no benchmark result shared by both models, so it does not support a quality verdict. Use the documented cost, context, and runtime rows instead. 0 results are shared. Category rows resting on Estimated evidence or different benchmark sets are marked directional and do not name a winner.

Model A
Mistral logo

Mistral

36.09/100

Estimated · Public rank #137

90% interval 24.6–47.6

Model B
OpenAI logo

OpenAI

36.25/100

Supported · Public rank #134

90% interval 20.1–52.4

Shared results
0
Mistral Medium 3.5 128B only
7
o1-preview only
0
Like-for-like categories
0 / 8
Estimated: Mistral Medium 3.5 128B · Supported: o1-previewHow the comparison works

Which one for your work

Recommendations appear only when a shared evidence basis or an explicit operating constraint supports the call. Secondary and unsupported use cases stay disclosed below the initial list.

  • Long documents

    Prompts that approach the documented context limit

    Mistral Medium 3.5 128B

    Mistral Medium 3.5 128B has the larger documented context window.

    Confidence: documented
  • Chat turn cost

    1K fresh input + 500 output tokens

    Mistral Medium 3.5 128B

    Mistral Medium 3.5 128B has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.

    Confidence: listed-rates
Show secondary and unsupported calls
  • Repository review cost

    50K fresh input + 3K output tokens

    Mistral Medium 3.5 128B

    Mistral Medium 3.5 128B has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.

    Confidence: listed-rates
  • Coding work

    Code generation, repair, and software-engineering tasks

    Not enough matched evidence

    Mistral Medium 3.5 128B and o1-preview are scored on Estimated evidence for coding, so the reading is directional rather than like-for-like.

    Confidence: limited
  • Agentic work

    Tool use, computer use, and multi-step task completion

    Not enough matched evidence

    O1-preview is not ranked on the public lane for agentic, so no winner is named for agentic.

    Confidence: limited
  • Cache-heavy agent loop cost

    200K cached + 20K fresh input + 10K output tokens

    Not enough matched evidence

    The page does not recommend a cost winner because at least one model cannot fit the stated workload in one request. o1-preview does not fit this workload in one request. Mistral Medium 3.5 128B has no published cached-input rate, so cached tokens use its listed input rate. o1-preview has no published cached-input rate, so cached tokens use its listed input rate.

    Confidence: rate-fallback

Which one for a specific job

Choose a job from the LLM Selector's task catalog to see the category row it rests on, under the same basis rules as the table below. A directional row stays directional; choosing a job never creates a winner.

The same task catalog as the LLM Selector. Each job names the evidence surface it rests on; nothing here adds a new score.

26.6Mistral Medium 3.5 128B23.6o1-preview

Directional only · BenchAlign v5.7

Mistral Medium 3.5 128B scores higher, but at least one score rests on Estimated evidence or a different benchmark set. Directional only, no winner.

Coding scores combine specific tasks and setups. Match the editor, harness, and effort to your workflow.

Same basis rules as the category table below

What is actually comparable

Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.

1 category rests on Estimated evidence or different evidence sets. Those rows remain visible for coverage context but do not name a winner.

Shape of the matched evidence

Only shared public evidence is shown. Sparse evidence stays a ruled list rather than being closed into a radar shape.

A shared-evidence shape is not available.

BenchLM does not draw a radar or infer missing axes when the matched evidence is too sparse.

Category results, on a stated basis

Each row shows the public-lane category score for both models: the BenchAlign v5.7 lane for agentic, coding, and knowledge, and the weighted public rows elsewhere, with the same rank each model page reports. A row is like-for-like only when both scores rest on Supported evidence or the same weighted set. Directional and not-comparable rows remain visible, but they never receive a winner.

Coding

Directional only
Mistral Medium 3.5 128B
26.6
Estimated · #102/143
o1-preview
23.6
Estimated · #110/143
Basis
BenchAlign v5.7 lane · 2 vs 0 public rows
Reading
Directional only

Agentic

Not comparable
Mistral Medium 3.5 128B
19.7
Supported · #100/117
o1-preview
Not ranked
Basis
BenchAlign v5.7 lane · 3 vs 0 public rows
Reading
Not comparable

Reasoning

Not comparable
Mistral Medium 3.5 128B
69.9
Unranked · 2 rankable rows
o1-preview
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Multimodal

Not comparable
Mistral Medium 3.5 128B
56.7
Unranked · 1 rankable row
o1-preview
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Knowledge

Not comparable
Mistral Medium 3.5 128B
33.6
Supported · #121/169
o1-preview
Not ranked
Basis
BenchAlign v5.7 lane · 2 vs 0 public rows
Reading
Not comparable

Multilingual

Not comparable
Mistral Medium 3.5 128B
Not ranked
o1-preview
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Instruction following

Not comparable
Mistral Medium 3.5 128B
82.6
#48/124
o1-preview
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Math

Not comparable
Mistral Medium 3.5 128B
Not ranked
o1-preview
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Ranks count the models scored in each category’s lane, so the agentic, coding, and knowledge denominators (BenchAlign v5.7) differ from the provisional-lane categories. Unranked scores sit on the provisional lane’s scale but never name a winner. Like-for-like rows within 0.5 points read as a practical tie.

Supported evidence per lane · bars run 0–100Methodology

What each workload costs

Three fixed token mixes turn per-token rates into comparable decisions. Each scenario states context fit and whether cached input had to fall back to the published list-input rate.

Chat turn

1K fresh input + 500 output tokens

Mistral Medium 3.5 128B
$0.00525
Fits in one request
o1-preview
$0.045
Fits in one request

Mistral Medium 3.5 128B has the lower modeled cost

Costs use the listed standard API rates.

Repository review

50K fresh input + 3K output tokens

Mistral Medium 3.5 128B
$0.0975
Fits in one request
o1-preview
$0.93
Fits in one request

Mistral Medium 3.5 128B has the lower modeled cost

Costs use the listed standard API rates.

Cache-heavy agent loop

200K cached + 20K fresh input + 10K output tokens

Mistral Medium 3.5 128B
$0.405
Fits in one request
Cached input priced at the published list-input rate
o1-preview
$3.90
Does not fit in one request
Cached input priced at the published list-input rate

o1-preview does not fit this workload in one request. Mistral Medium 3.5 128B has no published cached-input rate, so cached tokens use its listed input rate. o1-preview has no published cached-input rate, so cached tokens use its listed input rate.

Cached input falls back to the list input rate only where a cached rate is unpublished

Specification differences

Sourced differences are shown directly. Missing facts stay explicit instead of being inferred from a model name or family.

Context window

Maximum documented context; output-token limits may be lower.

Mistral Medium 3.5 128B

256K

o1-preview

200K

API model ID

Mistral Medium 3.5 128B

Not sourced

o1-preview

Not sourced

Cached-input rate

A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.

Mistral Medium 3.5 128B

Not published

o1-preview

Not published

Documented inputs

Mistral Medium 3.5 128B

Not sourced

o1-preview

Not sourced

Documented outputs

Mistral Medium 3.5 128B

Not sourced

o1-preview

Not sourced

Provider availability

Mistral Medium 3.5 128B

Not sourced

o1-preview

Not sourced

Reasoning profile

Mistral Medium 3.5 128B

Reasoning

o1-preview

Reasoning

Weight access

Mistral Medium 3.5 128B

Open Weight

o1-preview

Proprietary

License

Mistral Medium 3.5 128B

Open Weight

o1-preview

Proprietary

Release date

Mistral Medium 3.5 128B

2026-04-29

o1-preview

2024-09-12

If you already use one of these models

Deployment change
The models list different providers, so authentication, endpoint behavior, limits, and feature support may change.
Quality signal
The public evidence has no benchmark result shared by both models, so it does not support a quality verdict.
Workload cost
Repository review: $0.0975 vs $0.93. Cache-heavy agent loop: $0.405 vs $3.90.
Context tradeoff
Mistral Medium 3.5 128B has the larger documented window (256K).
Run the same representative tasks against both endpoints before changing production traffic.

Questions

Which is better, Mistral Medium 3.5 128B or o1-preview?

The public evidence has no benchmark result shared by both models, so it does not support a quality verdict. The page therefore keeps the decision tied to the specific documented workload.

Which is better for coding, Mistral Medium 3.5 128B or o1-preview?

Mistral Medium 3.5 128B scores higher for coding on the public lane, 26.6 to 23.6. Mistral Medium 3.5 128B and o1-preview are scored on Estimated evidence for coding, so the reading is directional rather than like-for-like. BenchLM does not name a winner for coding from a directional reading; read the shared benchmark rows directly and test the models on the same task set.

Which is better for agentic tasks, Mistral Medium 3.5 128B or o1-preview?

O1-preview is not ranked on the public lane for agentic tasks, so no winner is named for agentic tasks.

Which costs less, Mistral Medium 3.5 128B or o1-preview?

For the stated presets, chat costs $0.00525 on Mistral Medium 3.5 128B and $0.045 on o1-preview; repository review costs $0.0975 and $0.93; the cache-heavy agent loop costs $0.405 and $3.90. o1-preview does not fit this workload in one request. Mistral Medium 3.5 128B has no published cached-input rate, so cached tokens use its listed input rate. o1-preview has no published cached-input rate, so cached tokens use its listed input rate.

Which has the larger context window, Mistral Medium 3.5 128B or o1-preview?

Mistral Medium 3.5 128B has the larger documented context window: 256K, compared with 200K.

Benchmark evidence

The full public result ledger is available for audit without forcing a wide desktop table onto a phone.

Browse raw public benchmark evidence7 rows

Agentic

  • τ³-bench results

    Mistral Medium 3.5 128B91.4%
    Source
    o1-preview—

    Not directly comparable

  • Gert Labs

    Mistral Medium 3.5 128B39.10%
    Source
    o1-preview—

    Not directly comparable

  • Terminal-Bench 2.1 (Vals)

    Mistral Medium 3.5 128B39.0%
    Source
    o1-preview—

    Not directly comparable

Coding

  • SWE-bench Verified

    Mistral Medium 3.5 128B77.6%
    Source
    o1-preview—

    Not directly comparable

  • SWE-bench (Vals)

    Mistral Medium 3.5 128B66.4%
    Source
    o1-preview—

    Not directly comparable

Knowledge

  • GPQA Diamond (Vals)

    Mistral Medium 3.5 128B34.8%
    Source
    o1-preview—

    Not directly comparable

  • MMLU-Pro (Vals)

    Mistral Medium 3.5 128B75.3%
    Source
    o1-preview—

    Not directly comparable

7 public results · 0 shared

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Last updated September 29, 2026