DeepSeek V4.1 Flash hands-on tests and comparisons

On the same repo and prompt, 6.1 Sol finished in under half the time of DS 1017 with clearly higher intelligence, while DS 1017 even miscopied strings from the prompt.

A game developer says they've used up a second $200 account this week and is deciding between another subscription, going all-in on DeepSeek V4.1 Flash, or retrying Codex.

A roundup of a small survey comparing DeepSeek V4.1 Flash coding experience in Codex, Claude Code, Pi and the official DSH harness, arguing the harness shapes prompt, context compaction and tool use.

A user compares GPT-6.1 Terra with DeepSeek V4.1 Flash 1017: 1017 wins in some cases, but Terra is steadier, less AI-sounding and less prone to nonsense, and its API is cheaper at the same speed, suiting Codex users.

A user reports DeepSeek V4.1 (off-peak) outperforms Terra high at similar cost with faster API and better price-performance, while Terra max barely matches Sol medium at nearly 2x cost per task and runs at 25 tps in Codex.

Official DeepSWE v1.1 numbers across five harnesses range from mini-SWE at 74.2% to OpenCode at 65.5%, an 8.7-point spread for the same model.

Codex blocked the author's chat over a cybersecurity risk while testing a local security model, so they moved that work to DeepSeek V4.1 Flash, arguing refusals justify keeping more than one model.

A promotional post says DeepSeek V4.1 Flash 1017 is available in OpenCode, Claude Code, Pi and omp, scoring 77.0 on DeepSWE versus Opus 5's 74.0, while still trailing on Terminal-Bench at 42.3 vs 51.8.

On the 290-task index v2.0 cost frontier, Codex with DeepSeek V4.1 Flash scores 47.3 at $0.39 per task, versus 54.1/$1.50 for GPT-6.1 Sol, 54.7/$7.04 for GPT-6 Astra and 61.7/$11.42 for Claude Code with Opus 5.5.

The open-source Strata engine tiers GPU memory, RAM and SSD so DeepSeek V4.1 Flash quantized builds run on 12GB VRAM plus 46–64GB system RAM, with OpenAI/Anthropic-compatible APIs for Claude Code and Codex CLI.

A user says DeepSeek V4.1 Flash in DSH is now their main model, with difficult tasks sent to Codex running GPT-6.1 Sol high.

On the new Artificial Analysis coding agent index, Claude Code + Opus 5.5 leads at 61.7 for $11.42, GPT-6.1 Sol scores 54.1 for $1.50, and Codex + DeepSeek V4.1 Flash scores 47.3 for $0.39 per task.