Claude Opus 5 vs Step 3.5 Flash
As of Oct 15, 2026, Claude Opus 5 leads Step 3.5 Flash in 4 of 4 shared categories: General LLM, Reasoning, Long context, and Factuality.
Claude Opus 5
Close. Near-SOTA in Factuality, rank #4.
Step 3.5 Flash
#128 Best current rank: #128 in Factuality, as of Oct 15, 2026.
| Category | Claude Opus 5 | Step 3.5 Flash |
|---|---|---|
| General LLM | #11 · Was SOTA · General LLM Margin 5.851063829787236 LMArena leaderboard dataset · Oct 13, 2026 | #159 · #159 in General LLM Margin 84.57446808510639 LMArena leaderboard dataset · Oct 13, 2026 |
| Reasoning | #9 · Was SOTA · Reasoning Margin 5.319148936170208 LMArena leaderboard dataset · Oct 13, 2026 | #162 · #162 in Reasoning Margin 86.70212765957447 LMArena leaderboard dataset · Oct 13, 2026 |
| Math | #— · Not enough data Margin — LMArena leaderboard dataset · Oct 13, 2026 | #— · Not enough data Margin — LMArena leaderboard dataset · Oct 13, 2026 |
| Science | #12 · #12 in Science Margin — Epoch AI benchmarking hub · Jul 24, 2026 | — |
| Coding | #4 · #4 in Coding Margin 22.727272727272734 Terminal-Bench Harbor Hub · Oct 6, 2026 | #— · Not enough data Margin — LMArena leaderboard dataset · Oct 13, 2026 |
| Coding › Agentic | #4 · #4 in Coding › Agentic Margin 22.727272727272734 Terminal-Bench Harbor Hub · Oct 6, 2026 | — |
| Coding › Web dev | #6 · Near-SOTA · Coding › Web dev Margin 4 LMArena leaderboard dataset · Oct 13, 2026 | — |
| Long context | #9 · Was SOTA · Long context Margin 4.7872340425531945 LMArena leaderboard dataset · Oct 13, 2026 | #156 · #156 in Long context Margin 82.97872340425532 LMArena leaderboard dataset · Oct 13, 2026 |
| Vision | #12 · #12 in Vision Margin 36.8421052631579 Epoch AI benchmarking hub · Jul 24, 2026 | — |
| Factuality | #4 · Near-SOTA · Factuality Margin 2.9069767441860535 LMArena leaderboard dataset · Oct 13, 2026 | #128 · #128 in Factuality Margin 75 LMArena leaderboard dataset · Oct 13, 2026 |
| Abstraction (ARC) | #3 · #3 in Abstraction (ARC) Margin — Epoch AI benchmarking hub · Jul 24, 2026 | — |
Claude Opus 5: $10 per 1M blended tokens.
Step 3.5 Flash: $0.15 per 1M blended tokens.
Claude Opus 5: closed weights.
Step 3.5 Flash: open weights.
General LLM: As of Oct 15, 2026, Claude Opus 5 leads Step 3.5 Flash in General LLM at #11 against #159.
Reasoning: As of Oct 15, 2026, Claude Opus 5 leads Step 3.5 Flash in Reasoning at #9 against #162.
Long context: As of Oct 15, 2026, Claude Opus 5 leads Step 3.5 Flash in Long context at #9 against #156.
Factuality: As of Oct 15, 2026, Claude Opus 5 leads Step 3.5 Flash in Factuality at #4 against #128.
Claude Opus 5 · Step 3.5 Flash
Claude Opus 5 or Step 3.5 Flash?
As of Oct 15, 2026, Claude Opus 5 leads Step 3.5 Flash in 4 of 4 shared categories: General LLM, Reasoning, Long context, and Factuality.
Claude Opus 5 or Step 3.5 Flash for General LLM?
As of Oct 15, 2026, Claude Opus 5 leads Step 3.5 Flash in General LLM at #11 against #159.
Claude Opus 5 or Step 3.5 Flash for Reasoning?
As of Oct 15, 2026, Claude Opus 5 leads Step 3.5 Flash in Reasoning at #9 against #162.
Claude Opus 5 or Step 3.5 Flash for Long context?
As of Oct 15, 2026, Claude Opus 5 leads Step 3.5 Flash in Long context at #9 against #156.