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DeepSeek V4.1 Flash vs Claude Opus 5.5
Claude Opus 5.5 scores higher than DeepSeek V4.1 Flash on all 6 public leaderboards that rate both. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, DeepSeek V4.1 Flash is at 58.7 and Claude Opus 5.5 at 90.9 (out of 100).
Scores as published by each board; table composed November 13, 2026.
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Leaderboard by leaderboard
| Board | DeepSeek V4.1 Flash | Claude Opus 5.5 | Higher |
|---|---|---|---|
| LMArena Elo (community votes) | 1,663.7 | 1,814.7 | Claude Opus 5.5 |
| LiveBench global average (0-100) | 70.3 | 83.4 | Claude Opus 5.5 |
| SimpleBench AVG@5 % (private set) | 66.7 | 88.4 | Claude Opus 5.5 |
| Vals AI Vals Index accuracy % · weighted finance + coding tasks | 61.3 | 70.1 | Claude Opus 5.5 |
| Artificial Analysis intelligence index · measured runs only | 32.6 | 59.1 | Claude Opus 5.5 |
| Epoch AI Epoch Capabilities Index (ECI) · many benchmarks on one scale | 159.4 | 168.5 | Claude Opus 5.5 |
Raw scores are each board's own scale, so compare within a row, not across rows. Full table: the bench index.
For coding
On the ArtificialWatch coding index, DeepSeek V4.1 Flash is at 70.4 (#13 of 48) and Claude Opus 5.5 at 90 (#3). Claude Opus 5.5 scores higher on all 3 coding boards that rate both.
| Coding board | DeepSeek V4.1 Flash | Claude Opus 5.5 |
|---|---|---|
| LMArena · Coding | 1,503.8 | 1,543.4 |
| LiveBench · Coding | 80.4 | 87.1 |
| Vals Vibe Code Bench | 87.7 | 90.3 |
DeepSeek V4.1 Flash at a glance
- Developer
- DeepSeek
- Status
- Live since September 10, 2026
Live — Sep 10 · 1M ctx · $0.15/$0.60 per 1M as our sweep read it, which is DeepSeek's off-peak rate (peak hours on weekdays cost double, $0.30/$1.20, per its pricing page) · DeepSeek serves it under the unversioned id deepseek-flash, so the id itself never carries the version · Oct 17: upgraded in place to the 1017 checkpoint (DeepSeek-V4.1-Flash-1017, per DeepSeek's changelog), same deepseek-flash id and price, web and app updated too; open weights on Hugging Face as deepseek-ai/DeepSeek-V4.1-Flash-1017 (MIT, same config.json as the Sep 10 weights); OpenRouter lists it as deepseek/deepseek-v4.1-flash-1017 at $0.15/$0.60, 1M ctx, 384K max output · Oct 19: the Vals Index (updated Oct 18) scores the 1017 build 56.58%, #14 of 50 and the top open-weight model there, up from 51.32% for the Sep 10 build; $0.64 per test on Vals' run, against $0.33 for the Sep 10 build · Oct 19: DHS ordered DeepSeek products, and third-party products built on DeepSeek, excluded from and removed from US federal civilian agencies (Federal Register 2026-21447, publishing Oct 20) · Oct 20: DeepSeek open-sourced DeepInfer (Apache-2.0), the inference engine it serves V4.1 Flash with, for NVIDIA SM100 GPUs and Huawei Ascend 950 NPUs · Oct 20: Vals says the 1017 build completed 16.3 of 21 objectives on its coming offensive-cybersecurity benchmark, against 15.7 for GPT-6 Sol, on several times the tokens (a first finding; the full evaluation is due in the coming weeks).
DeepSeek open-sources DeepInfer, the engine behind V4.1 Flash, built for NVIDIA Blackwell and Huawei Ascend 950
2026-10-20 · DeepSeek released DeepInfer, the inference framework it says serves DeepSeek-V4.1-Flash at scale, as open source on October 20 under the Apache 2.0 license.
Vals: DeepSeek V4.1 Flash beat GPT-6 Sol on its offensive cybersecurity task, using about five times the tokens
2026-10-20 · Vals AI says DeepSeek V4.1 Flash 1017, an open-weight model, completed more objectives than OpenAI's GPT-6 Sol on a multi-step offensive cybersecurity task built on simulated corporate networks.
Claude Opus 5.5 at a glance
- Developer
- Anthropic
- Status
- Live since September 22, 2026
- API price
- $4 input / $20 output per 1M tokens · Anthropic, claude-opus-5-5
- Context window
- 1M tokens
Live — Sep 22 · $4/$20 per MTok, down from Opus 5 at $5/$25 · 1M ctx / 128K out · adaptive thinking always on, default effort medium · cache reads 5% of base input · Anthropic now says start here for most workloads, and Opus 5 is legacy · fast mode (speed: 'fast', up to 2.5x the output tokens per second by Anthropic's figure) at $8 / $40 per MTok, double standard, left research preview Oct 15 with no waitlist, access request or beta header; on the Claude API and on Claude in Microsoft Foundry (Azure-hosted), not on Bedrock, Google Cloud, Claude Platform on AWS, the Batch API or Priority Tier; @ClaudeDevs says Google Cloud is coming soon (Anthropic's fast mode docs, read Oct 16).
AI models go live a median of 4 months after their knowledge ends: Claude Opus 5.5 knows up to June 2026, Gemini 4 Argon only to March
2026-11-06 · Of the 22 live AI models whose labs publish a knowledge cutoff, the median went live 4 months after its training data ends, by ArtificialWatch's count. The latest published cutoff we found is June 2026, for Anthropic's four current Claude models and OpenAI's GPT-6.1 Terra.
SemiAnalysis launches GDPx: Opus 5.5 leads at 12%, Gemini 4 Carbon close behind
2026-11-02 · SemiAnalysis released GDPx on November 2, a new agentic benchmark of 206 tasks across 11 domains, and the best model it tested scores 12%. Claude Opus 5.5 leads at 12.0, Gemini 4 Carbon is second at 10.9 and GPT-6 Astra third at 9.6. We read the leaderboard directly at gdpx.semianalysis.com.
DeepSeek V4.1 Flash vs Claude Opus 5.5: quick answers
Which is better, DeepSeek V4.1 Flash or Claude Opus 5.5?
It depends on what you measure. Claude Opus 5.5 scores higher than DeepSeek V4.1 Flash on all 6 public leaderboards that rate both. Claude Opus 5.5's widest lead is on SimpleBench. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, DeepSeek V4.1 Flash is at 58.7 and Claude Opus 5.5 at 90.9 (out of 100).
Which is newer, DeepSeek V4.1 Flash or Claude Opus 5.5?
Claude Opus 5.5. It went live on September 22, 2026, 12 days after DeepSeek V4.1 Flash (September 10, 2026).
How do DeepSeek V4.1 Flash and Claude Opus 5.5 compare for coding?
On the ArtificialWatch coding index, DeepSeek V4.1 Flash is at 70.4 (#13 of 48) and Claude Opus 5.5 at 90 (#3). Claude Opus 5.5 scores higher on all 3 coding boards that rate both.
Who makes DeepSeek V4.1 Flash and Claude Opus 5.5?
DeepSeek V4.1 Flash is from DeepSeek; Claude Opus 5.5 is from Anthropic.
Where do these numbers come from?
Each score is the leaderboard's own published figure, read by ArtificialWatch (table composed November 13, 2026). Boards measure different things, so raw scores are only comparable within a row.
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