DeepSeek V4.1 Flash hands-on tests and comparisons

On two 128GB DGX Sparks, the author found NVIDIA's QAD-distilled GLM-5.3-Flash-FP4 clearly better than the DeepSeek-V4.1-Flash 2–3 bpw EXL3 builds he tested for coding and math.

Per Arena rankings, DeepSeek-V4.1-Flash-20261017 (Max) passes Kimi K3 (Max) to lead open models on WebDev at roughly 10x lower cost, a gap that compounds in agentic loops.

The author describes a one-day free trial of DeepSeek V4.1 Flash, getting an API key in OpenCode and claiming development flows more smoothly after spending Claude's $200 credit, demoed in a desktop app.

A Japanese walkthrough covers official claims of beating the prior version on all 11 tests and leading rivals on 4, off-peak pricing of $0.15/$0.6 per million tokens, DeepSWE 77.0 at about $0.2 per task, and npx installing the older 0.2.0-rc.2 harness.

Citing Arena's official leaderboard, V4.1-Flash-20261017 takes first among open models on Code Arena WebDev ahead of Kimi K3 (Max) and ranks 12th overall at 1670 points, ahead of Claude Opus 5 (High) and 10 points behind GPT-6 Sol (Max), at $0.3/$1.2 per million tokens, about 10x cheaper.

The author compares Opus 5.5 alone and paired with Sonnet 5.5, DeepSeek V4.1 Flash or Sol 6.1, finding Sonnet 5.5 sub-agents a waste of money and Opus+Sol the best cost-quality combo, while DeepSeek V4.1 Flash is too weak and needs more back-and-forth.

A roundup of DeepSeek's own numbers for the Oct 17 V4.1 Flash release: MIT-licensed 763B open weights with 1M context, DeepSWE 77.0 ahead of Opus 5's 74.0, but HLE 42.6 and Terminal-Bench 42.3 still behind Opus 5.

A user reports V4.1 Flash trades blows with Claude Opus 5.5 in web tests while costing $0.22 per task versus $2.35, under a tenth as much.

Peak hours (weekday 10-13 and 15-19 JST) price deepseek-flash output at $1.2 per million tokens versus $0.6 off-peak, and web search starts charging $0.75 per 1,000 calls from November 1.

An investor's take: V4.1 Flash already beats Opus 5 on some agent tasks at a tenth of the cost, which could compress premium pricing for US frontier models.

Roundup of DeepSeek 1017 hands-on reports: official channel TTFT ~1.5s vs Cline Pass up to 47s, Tier1 quality on a Unity skin task, and light use costing over ¥50/day.

A Portuguese-language post asks whether it would be a problem if the DeepSeek V4.1 Flash upgrade were distilled from Astra.