DeepSeek V4.1 Flash hands-on tests and comparisons

The author says GPU rental prices are surging and suggests buying used 30/40-series cards on Xianyu, unlocking cores with strata, and deploying DeepSeek V4.1 Flash, without providing any benchmark data.

On FrontierCode's maintainer-would-merge grading, Opus 5.5 in Claude Code scores 56.0% versus 52.6% for Codex with DeepSeek V4.1 Flash, at $11.42 vs $0.39 per task.

Four days after DeepSeek open-sourced its inference engine, vLLM claims parity with DeepInfer on V4.1-Flash decode and SGLang claims up to 7.4% faster with a repro guide.

The author plugged V4.1 Flash into the Claude Code terminal and spent 5.5 hours updating npm packages, project deps, WSL, Windows and a VPS OS for $0.45 total.

Same voxel-world prompt: two Sparks (EXL3 2.5bpw) took 73.7 min at ~70 tok/s decode with a 5.5/10 self-rating; four Sparks (4.0bpw) took 49.7 min at ~82 tok/s with 7.5/10, though differing quant and recipe versions prevent isolating Spark count.

A blog post compares DeepSeek V4.1 Flash 1017 with GPT-6/6.1 Sol and Claude Sonnet 5.5, including tips for paying less.

A developer built an Apple TV-style launcher with Opus 5.5 across 2,306 calls costing $173.85, while DeepSeek V4.1 Flash handled 893 lookups via llmgateway for $3.53, with screenshots and a DIY prompt in the post.

A TP2 EXL3 2.5bpw deployment across two DGX Sparks built a voxel world from one prompt in 73.7 minutes, writing 138,675 tokens with an 8.0/10 browser check and 70.5 tok/s code decode.

vLLM says its decode performance on DeepSeek-V4.1-Flash now matches DeepSeek's in-house DeepInfer from batch 8 to 256, after integrating the open-sourced kernels.

Q2 GGUF experts plus ~4-bit trellis dense layers cut bytes per token by 37% with bit-identical output, lifting single-user speed from 45 to 50 tok/s, 70 tok/s on code, and 8-user sharing from 96 to 108 tok/s.

The poster says upgraded GPUs and pruning got DeepSeek V4.1 Flash running locally, linking a Hugging Face page to apply, without disclosing hardware or speed numbers.

DeepSeek open-sourced DeepInfer, the engine behind V4.1 Flash, under Apache 2.0 on Oct 20; vLLM claims decode parity at batch sizes 8-256, while SGLang reports up to 1.04x prefill and 7.4% more decode throughput and notes DeepInfer lacks a KV cache system.