DeepSeek V4.1 Flash hands-on tests and comparisons

A translated Devsplainers video walkthrough: V4.1 Flash logged 4.5M sessions the day after opening free on OpenCode; covers picking free-tier models, disabling auto-recharge, the 200K context cap, and keeping confidential code out.

The author is porting TensorFold to dual Ampere A6000s in TP=2, keeping experts on the GPUs and other weights on a DGX Spark, with 384GB RAM and 96GB VRAM and about 75% of the code done.

On Coding Agent Index v2.0, Codex + DeepSeek V4.1 Flash scores 47.3 at $0.39 per task versus 61.7 at $11.42 for Claude Code + Opus 5.5 — about 29x the cost for +14.4 points.

A post contrasts Opus 5.5's $20 per million output tokens with DeepSeek V4.1 Flash's $1.20 and asks which one a startup would run on.

The poster says K3.1 Pro beats K3 but is far from Opus 5.5 in real work, and that cheaper DeepSeek V4.1 Flash still wins on real coding, calling the launch oversold.

The author recommends Flash (~$0.42/task, 57%, top open-source on Cyber) for repeated scanning and routine bug fixes, reserving GPT-6 Sol (~$1.77/task) for stricter attack-defense work where refusals matter.

OpenCode Go's $10/month plan shares a 60-coefficient pool; DeepSeek V4.1 Flash costs 0.75 per $1 (about $80 of usage) while Kimi K3.1 Pro costs 4 per $1.

An overview of the October 17 V4.1 Flash '1017' release: MIT-licensed open weights, 1M-token context, and a vendor-reported DeepSWE coding score of 77.0, runnable on private servers.

A quoted comparison says DeepSeek V4.1 Flash 1017 found 54 vulnerabilities for $7.53, seven more findings at roughly 16.6x lower cost than the other model.

On a single RTX 5090 with the Maya-S quant, DeepSeek Harness built a voxel sky world from one prompt in 74.1 min, scoring 8.5/10 in browser checks at 22.9 tok/s code decode, with blocks breaking up close.

On the same procedural Three.js coastal diorama prompt, V4.1 Flash took about 1 hour and 78M tokens versus MiniMax 3.1 Flash's ~2h17m and 60.3M tokens, both producing lighthouse, boat, water shaders, birds and night mode.

The author runs a single-agent MoA setup combining DeepSeek V4.1 Flash with Gyro S, letting Gyro serve as the perception layer, hoping it finishes before morning.