DeepSeek V4.1 Flash hands-on tests and comparisons

OpenCode says DeepSeek V4.1 Flash 1017 is now available on its Free and Go tiers, with no test results or specs provided.

The author coded for hours on DeepSeek Harness with V4.1 Flash 1017 via API at over 200 tok/s, spending roughly a dollar, while using Opus 5.5 only as an advisor.

On the same 3D video prompt, the author says GPT-6.1 Sol renders SOFT as soft while DeepSeek V4.1 Flash 1017's F and T look like plastic blocks.

Dedao's Xiaobu assistant switched to V4.1 Flash-1017 on Oct 18: median first-token time fell from 5.7s to 3.0s, slowest complex tasks from 28.7s to 11s, and truncation on 200 hard problems from 10% to 2%, with fewer tokens.

Arena reports DeepSeek-V4.1-Flash-20261017 (Max) ranks 11th overall on Agent Arena, the highest open model and ahead of Kimi K3 (Max).

The tester says 1017's agentic coding backend jumped from roughly GROK-4.6 level to domestic flagship level, but the model turned more conservative, needs a solid harness, and controls budget worse unless reminded each session.

Item 6 of a crypto and US-stock recap says DeepSeek released V4.1 Flash 1017 with its own search API, claiming gains in game development, 3D modeling and full project builds.

A user says free DeepSeek V4.1 Flash 1017 in DeepSeek Harness outperformed Opus in Claude Code and Sol in Codex on a data-scraping task.

A user tried DeepSeek V4.1 Flash-1017 across several video styles, reports good results, and includes the prompts used in the video.

The poster relays a claim that the 1017 build beats GPT-6 Astra on machine-learning research tasks and pushes back on distillation accusations, without giving test methods or numbers.

Peri Loom v1.1.6 was built fully by agents in four days at 2–3.3x the first quality release's performance, with Astra setting optimization direction and DeepSeek V4.1 Flash executing goals; next target is sqld-level performance.

A user moved coding to a local setup where Opus 5.5 reviews and plans, then the local deepseek harness CLI writes code with V4.1 Flash, saying it beats pure Cursor cloud use and saves quota.