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DeepSeek V4.1 Flash max vs Pareto 26.9 medium

No clear quality winner: Pareto 26.9 medium won 12, DeepSeek V4.1 Flash max won 7, 5 tied; DeepSeek V4.1 Flash max leads on cost: 25.4× cheaper; Pareto 26.9 medium leads on agent time: 1.3× faster.

24 tasksData from

Stet score

DeepSeek V4.1 Flash maxdeepseek-harness · max reasoningRank 11 of 16

45.995% range 35.5–56.1

Pareto 26.9 mediumclaude-code · medium reasoningRank 7 of 16

57.195% range 47.0–66.711.2 points higher

A directional read: their 95% score ranges overlap.

Cost / task

DeepSeek V4.1 Flash max$0.4925.4× cheaperfrom 23/24 tasks
Pareto 26.9 medium$12.47

Agent time / task

DeepSeek V4.1 Flash max49.3 min
Pareto 26.9 medium39.2 min1.3× faster

Quality

Head-to-head matchups

DeepSeek V4.1 Flash max won7

Tied5

Pareto 26.9 medium won12

Pareto 26.9 medium’s win share 59%, 95% range 43–76%Ties are within judge noise.

Task by task

DeepSeek V4.1 Flash max solved 2 tasks that Pareto 26.9 medium didn’t, and Pareto 26.9 medium solved 3 that DeepSeek V4.1 Flash max didn’t. Both solved 10; neither solved 9.

DeepSeek V4.1 Flash max only 2

  • stet-commit-5d766ddePassed tests
  • stet-commit-342d0ac0Equivalent to the merged fix

Pareto 26.9 medium only 3

  • stet-6f84e978Passed tests
  • stet-2450ca2dPassed tests
  • stet-commit-f8ae1177Passed tests

A task counts as solved when its tests passed or a judge found the fix equivalent to the merged change, as in the leaderboard’s Solved column. Stet score also weighs code quality, so it can order the two differently.

All 24 compared tasks
Task by task
TaskDeepSeek V4.1 Flash maxPareto 26.9 mediumSolved by
stet-3169aefaPassed testsPassed testsBoth
stet-89dfbc27Passed testsPassed testsBoth
stet-b28f4fe7Passed testsPassed testsBoth
stet-232b50baPassed testsPassed testsBoth
stet-5276aa3fPassed testsPassed testsBoth
stet-commit-bbbbae09Passed testsPassed testsBoth
stet-66762b4cPassed testsPassed testsBoth
stet-15439c21Passed testsPassed testsBoth
stet-commit-5d766ddePassed testsFailedDeepSeek V4.1 Flash max only
stet-43493c52Passed testsPassed testsBoth
stet-commit-f0caded9Passed testsEquivalent to the merged fixBoth
stet-6f84e978FailedPassed testsPareto 26.9 medium only
stet-2450ca2dFailedPassed testsPareto 26.9 medium only
stet-commit-342d0ac0Equivalent to the merged fixFailedDeepSeek V4.1 Flash max only
stet-commit-f8ae1177FailedPassed testsPareto 26.9 medium only
stet-commit-60a0e6c2FailedFailedNeither
stet-commit-5e075641FailedFailedNeither
stet-commit-2826765eFailedFailedNeither
stet-commit-a8716b88FailedFailedNeither
stet-commit-e928166fFailedFailedNeither
stet-commit-30506f8eFailedFailedNeither
stet-commit-87814583FailedFailedNeither
stet-commit-d2ab0c25FailedFailedNeither
stet-commit-e41c2e2dFailedFailedNeither

Side by side

Side by side
MetricDeepSeek V4.1 Flash maxPareto 26.9 medium
Harnessdeepseek-harnessclaude-code
Reasoning effortmaxmedium
Rank11 of 167 of 16
Stet score45.995% range 35.5–56.157.195% range 47.0–66.7
Solved12/2411 passed, 1 judged equivalent13/2412 passed, 1 judged equivalent
Cost / task$0.49from 23/24 tasks$12.47
Agent time / task49.3 min39.2 min

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About this data

  • 24 tasks, each a merged change replayed from the repo as it was just before the merge.
  • Data from .
  • Both setups come from the same leaderboard run of 16 setups: bmk_d4ba310fdf50db4ccb2092e3.

See all 16 setups on the leaderboardHow Stet measures