DeepSeek V4.1 Flash hands-on tests and comparisons

Per DeepSeek, the open-weight release scores 42.3 on Terminal-Bench 4.0 and 77.0 on DeepSWE v1.1 (Claude Opus 5: 74.0), with off-peak API pricing of $0.15 input / $0.60 output per 1M tokens.

A roundup of user reviews says V4.1 Flash is fast but over-thinks and slows down, feels over-marketed, trails Opus and Astra on real dev tasks, may be distilled from GPT data, yet works as an Opus 5.5 substitute.

The author reports successfully wiring DeepSeek V4.1 Flash into Claude Code through OpenCode Go, contrary to what ChatGPT and Gemini said about OpenCode not exposing an Anthropic endpoint.

OpenRouter's past-week usage top five are all Chinese models, with V4.1 Flash at 32.8 trillion tokens, over five times sixth-place GPT-6 Luna.

A LobsterAI report shows DeepSeek V4.1 Flash has the highest cache hit rate at 97% under the same harness, with cache pricing around 2% of list price, which the author says explains its perceived cost advantage better than unit price.

A user says they are running original weights with a small -1017 tweak on the spark-vllm-docker three-Spark DeepSeek V4.1 Flash recipe for local deployment.

A Japanese user notes widespread complaints about DeepSeek V4.1 Flash's token efficiency and is torn about sticking with GLM-5.3-Flash instead.

DeepSeek-V4.1-Flash-20261017 scores 1670 on Code Arena WebDev, ranking first among open models and 12th overall, ahead of Claude Opus 5 (High) and within 10 points of GPT-6 Sol (Max), at $0.3/$1.2 per million tokens.

The author replaced Codex's model backend with DeepSeek V4.1 Flash on Ollama, lists per-million-token cache-hit and cache-miss prices, and splits usage between Ollama by day and the official API at night.

Native Mia/SGLang versus TensorFold EXL3 3.5bpw over dual RoCE: single-request throughput rises from 79.2 to 97.7 tok/s, 16-concurrency falls from 434.7 to 267.6, and 128K first-token latency goes from 26.9 to 55.3 seconds.

The author combined NASA footage with code-rendered timers and tick marks, using no stock video, and says the result beat expectations; prompt shared in comments.

The poster says V4.1 Flash 1017 feels highly similar to GPT-6 Astra in use and has heard their model fingerprints are close too, without offering concrete tests.