DeepSeek V4.1 Flash hands-on tests and comparisons

A circulating comparison puts Opus 5.5 at 20 minutes and $6 versus V4.1 Flash at 1 hour and $0.23 on the same task, with the poster noting nobody prices waiting time.

The poster claims V4.1-Flash-1017 outperforms 6.1SOL on real work and is faster, making them rethink their Codex subscription.

Same long prompt, no skills: both made a DeepSeek Harness promo video, and the author still rates Opus 5.5 as the leader in this domain.

A test shows DeepSeek V4.1 Flash 1017 scoring 128/157 (81.5%) on Cold Iron with zero errors, noting only reasoning.effort=none actually disables thinking.

Same prompt to rebuild the Tesla Roadster event in voxel 3D: DeepSeek cost $0.89 versus $1.07 for GPT-6 Luna, with different detail and style; a single test only.

The author suggests DSH for low-cost calls, Codex for daily development, and Claude Code for validating complex tasks, noting that tool calling and context management after integration are the key factors.

A same-task comparison finds DeepSeek V4.1 Flash 1017 a tier below Opus 5.5 and around Sonnet 5.5 level, while costing $0.23 versus $6.

A user breaks down official numbers: Terminal-Bench 4.0 31.2→42.3, ProgramBench 20.3→29.1, HLE 36.8→42.6, ahead of Opus 5 on agent tests but behind on HLE (42.6 vs 56.3); his own animation test needed a rerun, took 24 minutes and cost 2 cents less.

About an hour produced spring, autumn, winter and rainy-night scenes, better than Kimi on the first pass, but the rainy night turned all blue silhouettes and stayed broken after multiple fixes.

Atomic Chat ran the same voxel stunt-track build task: V4.1 Flash 1017 cost $0.89 versus $1.07 for GPT-6 Luna, about 17% cheaper with similar visuals.

A user reports DeepSeek-V4.1-Flash works great for everyday agent use like Hermes, calling Luna dumb and slow by comparison and Haiku pricey past 100k context.

A detailed review finds V4.1 Flash strong value: code-generated video second only to Opus/Sonnet 5.5, Max thinking effective, ~15% fewer tokens and 15–20% faster than the prior gen, plus its own search API.