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Claude Opus 5.5 vs DeepSeek-V4.1-Flash-1017: which delivered after 7 days?
Same stamp after day 7: both Claude Opus 5.5 and DeepSeek-V4.1-Flash-1017 are stamped Partly. The claim tallies below show where each one held and where it didn't.
| Claude Opus 5.5 | DeepSeek-V4.1-Flash-1017 | |
|---|---|---|
| Verdict | Partly | Partly |
| Claims held | 0 | 2 |
| Claims mixed | 3 | 2 |
| Claims failed | 0 | 0 |
| Claims unclear | 2 | 0 |
| User reports | 7 | 12 |
| Launched | 22 Sept 2026 | 17 Oct 2026 |
| Last stamped | 22 Oct 2026 | 25 Oct 2026 |
No. 002 · Anthropic
Claude Opus 5.5
The lower list price is real, but users report limits draining faster, more thinking tokens and safeguard false alarms, and nobody has independently confirmed the 40% saving.
- Launched
- 22 Sept 2026
- Stamped
- 22 Oct 2026
- Claims
- ✓0 held · ~3 mixed · ✗0 failed · ?2 unclear
- Reports
- 7 (1 praise · 6 problem · 0 mixed)
What they claimed
“It performs at the level of Claude Fable 5.1 on most work and costs 40% less to run than Opus 5.”~ Mixed
“Input and output tokens are $4 and $20 per million, 20% less than Opus 5.”? Unclear
“In addition to the price drop, we’re increasing five-hour usage limits on Pro, Max, Team, and seat-based Enterprise plans.”~ Mixed
“It is much less likely than recent models to take hard-to-reverse actions or act outside the boundaries it’s been given”~ Mixed
“Opus 5.5 also generates output more than 30% faster than Opus 5.”? Unclear
No. 008 · DeepSeek
DeepSeek-V4.1-Flash-1017
It is live and MIT-licensed as promised, but users split on whether it finishes faster and codes better; some see shorter runs, others overthinking.
- Launched
- 17 Oct 2026
- Stamped
- 25 Oct 2026
- Claims
- ✓2 held · ~2 mixed · ✗0 failed · ?0 unclear
- Reports
- 12 (4 praise · 4 problem · 4 mixed)
What they claimed
“Now live on our website, app, and API.”✓ Holds
“Stronger benchmark performance, faster task completion, and shorter outputs than the previous version”~ Mixed
“DeepSeek-V4.1-Flash-1017 uses reinforcement learning with self-feedback to improve end-to-end project development”~ Mixed
“This repository and the model weights are licensed under the MIT License.”✓ Holds
Both stamps come from the public user reports linked on each receipt, under the same method. Verdicts are opinion and are never paid for.
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