DeepSeek V4.1 Flash hands-on tests and comparisons

A four-point take on the upgrade: shorter outputs cut inference cost, tooling optimizations target DeepSeek Harness and CodeBuddy, strong DeepSWE and Terminal-Bench scores reinforce the price-performance pitch, and same-day rollout across site, app and API drives usage.

The user argues DeepSWE has become a joke of a benchmark and manually inserted V4.1 Flash 1017 results into a CodingFleet blog screenshot.

A user says after a Claude ban they used DeepSeek V4.1 Flash with open-source OpenDesign Motion to produce a brand motion video from one prompt, calling it an Opus 5.5 alternative.

A long Japanese post analyzes performance, pricing, the 763B open weights and post-training, citing 77% DeepSWE success versus about 75% for GPT-6.1 Sol at roughly one-third the cost.

A Japanese poster suggests putting Grok Bot at the top, letting Claude Code split tasks per project, and delegating execution to Devin SWE-2 and free OpenCode models.

Despite being labeled a minor update, V4.1-Flash-1017 reportedly outperforms GPT-5.6 Sol and Opus 5 on several published agent and coding benchmarks with shorter outputs and faster completion.

Hands-on speed reaches 244 tok/s and nearly 300 at peak, faster than GPT-6.1 Sol's Ultrafast mode with intelligence near GPT-5.6 Sol; it adds built-in web research, is free on the official harness until Oct 31, and shows clear coding and 3D gains.

The author made V4.1-Flash-1017 the default in Hermes for all-day recurring tasks and research, citing off-peak pricing of $0.15 input / $0.60 output per million tokens, and plans to report actual token usage and cost per task.

The poster says the model appears to have shown up on the API platform before any announcement and asks whether anyone has called it and how speed, price and coding perform; no test data yet.

AIHubMix ran both versions on the same prompt at max reasoning: the older build took ~20 min and $0.50, the 1017 build ~17 min and $0.46.

A user reports the overseas V4.1-Flash gives roughly 100M free tokens per day through month-end, and notes DeepSeek opened its own search API at about ¥5 per 1,000 queries.

The author focuses on agent cost and latency: DeepSeek reports shorter outputs, faster task completion and unchanged API pricing, with Terminal-Bench 4.0 at 42.3 and DeepSWE v1.1 at 77.0, though scores depend on the harness.