DeepSeek Explained: What It Is, How It Works, and Whether to Trust It

 


DeepSeek: The Chinese AI That Shocked Silicon Valley — Full Analysis

On January 27, 2025, Nvidia lost $589 billion in market capitalization in a single trading session — the largest single-day value wipeout of any company in U.S. stock market history. The trigger was a chatbot from a hedge fund in Hangzhou, China, that claimed it had matched the reasoning capabilities of OpenAI's best model for $5.6 million. The number that detonated the market wasn't the performance claim. It was the cost. American labs had spent hundreds of millions, in some cases billions, on training runs that DeepSeek was allegedly compressing into pocket change. If that was true, the entire investment thesis behind AI infrastructure — the GPU arms race, the data center buildout, the $500 billion Stargate Project — rested on an assumption that was now being questioned in real time.

Most coverage of DeepSeek collapsed almost immediately into two camps: breathless celebration of a Chinese underdog defeating Silicon Valley, or reflexive dismissal of a propaganda operation dressed up as a technical paper. Neither position survived contact with the actual evidence. The $6 million figure was misleading. The safety record was a real problem. The architecture was a genuine engineering achievement. The geopolitical implications were, and remain, unsettled. What DeepSeek actually represents is more complicated than either camp wanted to admit.

This article reconstructs the full picture: where the cost claim came from, what it omitted, what the technology actually does, where it falls short, and why the question of whether to use it cannot be answered without first deciding who you trust with your data.

  1. The Man Who Started a Hedge Fund to Build an AI
  2. What the Architecture Actually Does
  3. The $6 Million Figure — What It Included and What It Left Out
  4. Benchmarks: Where DeepSeek Wins, Where It Doesn't
  5. The Distillation Allegation
  6. Privacy, Censorship, and the Legal Environment in China
  7. What the Market Reaction Was Really About
  8. Who This Is For — And Who It Isn't
  9. Verdict
  10. FAQ

The Man Who Started a Hedge Fund to Build an AI

Liang Wenfeng did not come from a tech company. He co-founded High-Flyer, a quantitative hedge fund in Hangzhou, in 2015, running algorithmic trading strategies built on machine learning. By 2021, High-Flyer's assets had grown past 100 billion yuan — roughly $14 billion — and Liang had become convinced that the same mathematical optimization his traders used to find patterns in financial markets could be applied to something larger. He started buying Nvidia GPUs.

A business partner described the early conversations as puzzling. "When we first met him, he was this very nerdy guy with a terrible hairstyle talking about building a 10,000-chip cluster to train his own models," the partner told the Financial Times. "We didn't take him seriously." By 2022, High-Flyer had accumulated roughly 10,000 A100 chips — before the Biden administration's export restrictions made such a purchase impossible. That hardware stockpile, acquired before the window closed, became the foundation on which DeepSeek was built. DeepSeek was formally established in July 2023, with Liang holding an 84% personal stake through two shell corporations. The stated goal was not commercial: not to build a product, not to compete with ByteDance. To reach the frontier of artificial general intelligence, regardless of profit.

That origin explains more about DeepSeek than any benchmark. A quant fund's core competency is squeezing performance out of constrained resources — finding the trade that costs less and earns more. When U.S. export controls cut off access to H100 chips, the most capable GPUs Nvidia makes, DeepSeek's engineers did what their hedge fund founders had always done: they found a more efficient path. Liang himself acknowledged the constraint plainly in a July 2024 interview: "The problem we are facing has never been funding, but the export control on advanced chips." Using H800s — a degraded variant Nvidia created specifically for the Chinese market — required, by his own estimate, two to four times the compute of an equivalent H100 run to achieve the same result. That penalty forced an architectural rethink that would eventually produce a model Silicon Valley had not anticipated.

What the Architecture Actually Does

DeepSeek V3, released in December 2024, is a Mixture-of-Experts model — not a new concept, but an old one executed at a scale and precision that changed what people thought the approach could achieve. According to DeepSeek's own technical report, the model carries 671 billion total parameters but activates only 37 billion of them for any given token. That 5.5% activation ratio is the number that matters most and that typical coverage ignores.

Dense models — GPT-4, Claude — activate all of their weights on every token. A 70 billion parameter dense model uses 70 billion parameters every time it processes a word. A 671 billion parameter MoE model like DeepSeek V3 uses only 37 billion, routing each input to a small set of specialized sub-networks from a pool of 256 fine-grained experts plus one shared expert. The router — a gating mechanism — makes the selection. As one technical analysis explains it, total parameters determine what the model knows; active parameters determine what it costs to think. A 671B MoE model doesn't know less than a 671B dense model. It just accesses its knowledge selectively, which makes inference dramatically cheaper.

DeepSeek also built Multi-Head Latent Attention — a compression technique for the key-value cache that powers the attention mechanism in transformers. According to the SemiAnalysis report on DeepSeek's infrastructure, MLA cuts inference costs by 93.3% through reduced KV cache usage. This is the engineering achievement that actually drives down per-token cost in deployment. It is also, notably, the innovation that Western labs were quickest to examine for potential adoption. When competitors are reverse-engineering your efficiency techniques, that is a signal about the quality of the underlying work.


"DeepSeek's work illustrates how new models can be created using that technique, leveraging widely-available models and compute that is fully export control compliant." — Nvidia, official statement, January 27, 2025

The R1 model, released in January 2025, added a reasoning layer on top of V3's architecture. Unlike OpenAI's o1, which was trained with a mixture of supervised fine-tuning and reinforcement learning, DeepSeek-R1 was trained primarily through reinforcement learning without supervised fine-tuning at the initial stage — a methodological choice that produced a model capable of chain-of-thought reasoning while revealing more of its internal reasoning process than competing models typically show. On AIME 2024, a competition mathematics benchmark, R1 scored comparably to OpenAI's o1. On MMLU, it posted 90.8% against o1's 91.8%. On DROP, a reading comprehension benchmark, R1 outperformed o1.

Where DeepSeek trails is in agentic coding — tasks that require sustained autonomous operation across multiple files and real-world software repositories. On SWE-bench Verified, which tests models against actual GitHub issues, Claude leads at 80.9%, DeepSeek at 78%, and GPT-4 at 72%. That gap is real, and developers running complex autonomous coding pipelines will feel it.

The $6 Million Figure — What It Included and What It Left Out

DeepSeek's technical report stated that V3 was trained using 2,788,000 GPU-hours on H800 chips. At an estimated market rate of $2 per GPU-hour, that comes to $5.576 million — the figure that detonated markets and dominated headlines. Paul Triolio, senior VP for China and technology policy at advisory firm DGA Group, told CNBC the figure represented only one training run, and that "the overall cost was likely significantly higher, but still lower than the amount spent by major U.S. AI companies."

SemiAnalysis, an independent semiconductor research firm that had been tracking DeepSeek for over a year, published a deeper accounting. Their analysis estimated DeepSeek's total server capital expenditure at $1.3 to $1.6 billion, with roughly $944 million in operating costs for maintaining GPU clusters. Demis Hassabis, head of Google DeepMind, called the claim "exaggerated and a little bit misleading," noting that DeepSeek "seems to have only reported the cost of the final training round, which is a fraction of the total cost."

The $6 million figure excluded research and development expenditure, infrastructure build-out, failed training runs, the cost of the H800 and H100 chips themselves, and years of experimentation on prior models going back to DeepSeek-LLM in November 2023. It is the equivalent of reporting the cost of a bridge by citing only the final day of construction labor. The number was not false — the compute cost of that particular training run was approximately what DeepSeek reported. It was, however, a selective disclosure that made an extraordinary claim without providing the context required to evaluate it.

DeepSeek's reported $5.6M training cost covered GPU pre-training expenses only. SemiAnalysis estimated total server CapEx at $1.3–1.6 billion, with $944M in operating costs — roughly 216 times the headline figure.

None of this means DeepSeek's efficiency is not real. The architectural innovations — MoE routing, MLA, FP8 mixed-precision training — do genuinely reduce the compute required per training run relative to comparable dense models. The V3 model was trained on 14.8 trillion tokens using less compute than Meta's Llama 3.1 consumed for a model with far fewer total parameters. That efficiency advantage is documented and reproducible. What is not reproducible by a team without DeepSeek's resources is the years of prior research, the hardware investment, or the infrastructure required to run the model at scale.

Benchmarks: Where DeepSeek Wins, Where It Doesn't

DeepSeek V3.2 scores 88.5 on MMLU, placing it slightly ahead of GPT-4o at 87.2 and competitive with Claude Sonnet on general knowledge tasks. On coding, V3 and Claude Sonnet both reach approximately 85% on HumanEval. On mathematics, DeepSeek R1's performance on AIME 2025 is competitive with the best reasoning models OpenAI has deployed. These are not the benchmarks that publications tend to run when they want a dramatic headline.

The benchmarks that reveal the gap are the ones measuring real-world software engineering. SWE-bench Verified — created by testing models against actual unresolved GitHub issues from open-source repositories — shows Claude maintaining an advantage in multi-file refactoring and complex autonomous coding tasks. For a developer who needs a model to run unsupervised across a large codebase for hours, this matters. For a developer generating boilerplate or working through isolated problems, the delta is negligible and the price difference is not.

On instruction-following and nuanced task completion, independent evaluations consistently show DeepSeek trailing Claude and, to a lesser extent, GPT-4o. The model handles complex mathematical and scientific tasks with impressive accuracy, but asks requiring sustained contextual awareness across long interactions surface weaknesses that do not appear in single-pass benchmark tests.

Creative writing is where DeepSeek falls farthest behind. The outputs are technically correct and structurally sound. They do not, however, feel like writing. This limitation matters less than it sounds for most professional use cases and matters enormously for anyone who actually intends to publish what the model generates.

Pricing at time of writing (DeepSeek API): DeepSeek V3 — approximately $0.27 per million input tokens, $1.10 per million output tokens. DeepSeek R1 — approximately $0.55 per million input tokens, $2.19 per million output tokens. For comparison, OpenAI o1 charges $15 per million input tokens and $60 per million output tokens. Figures reflect the latest available data at time of writing. Always verify current pricing with official sources.

The Distillation Allegation

In late January 2025, OpenAI told Axios it had identified evidence of distillation attempts by China-based groups targeting its models. Distillation, in AI development, means training a smaller model using the outputs of a larger one — a legitimate technique when used with permission and a terms-of-service violation when applied to a competing model's API without authorization. An OpenAI spokesperson said the company was "reviewing indications that DeepSeek may have inappropriately distilled our models."

The specific evidence cited was behavioral: one analysis found DeepSeek's answers 74.2% similar in writing style to ChatGPT's responses — a degree of similarity that researchers argued was difficult to explain without training on ChatGPT outputs. Microsoft, which hosts OpenAI's infrastructure on Azure, identified clusters of API accounts engaging in rapid-fire complex queries routed through obfuscated third-party proxies, behavior the companies described as consistent with systematic data harvesting. In February 2026, OpenAI sent a formal memorandum to the House Select Committee on China explicitly alleging ongoing intellectual property theft.

DeepSeek denied the allegations. The legal question remains genuinely open. As Winston & Strawn's legal analysis notes, OpenAI's own terms of use assign output ownership to users, not to OpenAI — a provision that complicates any copyright claim over distilled model outputs. OpenAI itself has faced copyright suits for training on publicly available data and argued fair use as a defense, a position that makes it harder to argue that DeepSeek's similar practices cross a clear legal line. The irony sits in plain view. It does not resolve anything about what actually happened.

What the allegation does illuminate is a structural vulnerability in the AI industry. A model trained on the outputs of a frontier system can inherit much of that system's reasoning capability while potentially shedding the safety constraints built into it — exactly the concern expressed by congressional staff. Whether or not DeepSeek did this deliberately, the technique is documented, effective, and increasingly understood.

Privacy, Censorship, and the Legal Environment in China

DeepSeek stores user data on servers in China. That single fact, combined with Chinese cybersecurity and national security law, defines the privacy risk in full. Under Chinese law, companies must cooperate with and assist intelligence efforts, with no legal recourse to resist — a structural difference from the U.S. system, where agencies generally require a court order and companies retain the right to challenge such orders in court. Western companies can push back. DeepSeek cannot.

In January 2025, cybersecurity firm Wiz reported that DeepSeek had accidentally left over one million lines of sensitive data exposed on the open internet — including chat logs, API keys, and backend system details. The database was publicly accessible with no authentication required. Wiz researchers found it within thirty minutes of looking. It was locked down within thirty minutes of Wiz contacting DeepSeek, but whether it had been accessed in the interim is unknown.

Feroot Security separately identified hardcoded links in DeepSeek's web login page connecting it to China Mobile, a state-owned telecommunications company that has been banned from operating in the United States over national security concerns. The U.S. House Select Committee on the Chinese Communist Party, in a March 2025 report, characterized DeepSeek as a national security threat, citing data flows to China and the legal environment governing those flows. The committee's own testing found that approximately 85% of politically sensitive topics it examined were suppressed or altered in DeepSeek's responses.

Testing confirms the censorship pattern. Ask DeepSeek about the 1989 Tiananmen Square massacre: it deflects. Ask about Taiwan's sovereignty: it begins an answer and then replaces it with a message that the topic is beyond its scope. Ask whether Russia's invasion of Ukraine was justified: it repeats China's official neutrality framing. These are not edge cases. They are the model operating as Chinese content regulations require it to operate. China's Interim Measures for the Management of Generative Artificial Intelligence Services mandate that AI outputs uphold "core socialist values" — and the model was built to comply.

There is a meaningful mitigation available to technically capable users: self-hosting the open-weight model. Running DeepSeek on your own infrastructure eliminates the data transfer to Chinese servers entirely and removes the censorship applied by DeepSeek's hosted service. The model weights are available under a permissive MIT license. What self-hosting does not change is the question of what was embedded during training, which remains harder to audit than what is filtered at inference time.

Silence is not safety. The absence of a confirmed breach does not mean data accessed via DeepSeek's servers is not at risk.

What the Market Reaction Was Really About

Nvidia's 17% drop on January 27, 2025, erasing $589 billion in market value in a single session, was not a rational response to DeepSeek's model release. Nvidia's GPUs were used to train DeepSeek. Nvidia's GPUs are used to run DeepSeek in inference. More efficient AI models do not reduce GPU demand — they expand it by making AI economically viable for more applications at lower cost. This is the argument Nvidia made in its official statement, and analysts at Cantor Fitzgerald agreed, calling the sell-off a misreading of the implications.

What the market was actually pricing was a question about the investment thesis, not the hardware. If AI capability could be achieved at a fraction of the cost assumed, then the hundreds of billions pledged by Microsoft, Meta, and Google for GPU infrastructure might be premature. If the $500 billion Stargate Project, announced by President Trump a week before DeepSeek's release, rested on an assumption about the compute intensity of frontier AI that DeepSeek was now challenging, then the entire buildout might be sized wrong.

Marc Andreessen called it "AI's Sputnik moment." The comparison is historically instructive but not quite right. Sputnik demonstrated Soviet capability in a domain where Americans had assumed advantage. DeepSeek demonstrated that the economic assumptions underlying American AI investment were not as settled as they appeared. Those are related but different shocks. Sputnik triggered a space race. DeepSeek triggered a cost re-evaluation, which is a quieter but potentially more consequential disruption.

By the end of the week, Nvidia had recovered roughly half of the loss. The executives at Microsoft and Meta reaffirmed their capital expenditure plans. Sam Altman said DeepSeek was "an example of the impact of open-source AI" that didn't change OpenAI's trajectory. The immediate panic subsided. The underlying question — whether the economics of frontier AI had changed — did not.

Who This Is For — And Who It Isn't

You are a developer at a startup, running 50 million tokens a day through an API to power a document analysis tool. At OpenAI's o1 pricing, that costs roughly $3,000 per day. At DeepSeek's V3 pricing, it costs approximately $55. The performance difference on your specific task — extracting structured data from unstructured text — is not measurable by your users. The pricing difference is existential for your runway. In that scenario, DeepSeek is not a consideration. It is the obvious choice, provided you are not processing data you are legally or contractually obligated to protect.

You are a researcher at a university working on mathematics or formal reasoning tasks. R1's performance on AIME and MATH-500 is competitive with the best models available, at a cost that does not require grant funding to access. Your inputs are not sensitive. You are running the model locally on your institution's hardware. DeepSeek serves this use case well.

You are a government contractor, a healthcare organization, a legal firm, or anyone handling data subject to HIPAA, GDPR, or security clearance requirements. DeepSeek's hosted service is not available to you in any compliant configuration. The data storage location alone disqualifies it. Self-hosting the open weights is theoretically possible but requires infrastructure investment that negates most of the cost advantage. You are not this model's audience.

You are a journalist, a researcher, or a policy analyst asking questions about Chinese foreign policy, Taiwan, Xinjiang, or Tiananmen. DeepSeek will either refuse to answer or provide responses shaped by Chinese government content regulations. The information you receive is not neutral. Use a different tool.

Verdict

DeepSeek is a genuine engineering achievement built on architectural innovations — Mixture-of-Experts routing and Multi-Head Latent Attention — that produce frontier-level performance at pricing no Western lab currently matches. The $6 million training cost headline was misleading. The actual infrastructure investment was orders of magnitude higher. The performance claims, however, hold up under scrutiny for most benchmark categories, with a real but narrowing gap in agentic coding and a pronounced gap in creative writing.

The recommendation is use-case specific:

  • Use the API for cost-sensitive technical tasks where data is not sensitive and regulatory compliance is not at stake — the price difference is real and large.
  • Self-host the open weights if you need the cost advantage without the data risk — the MIT license permits it, and the censorship of the hosted service is removed at inference time.
  • Do not use the hosted service for any data that carries legal protection or that a reasonable person would consider sensitive. The Chinese data-storage environment is not a theoretical risk.
  • Do not use DeepSeek for political or geopolitical research — the responses are shaped by Chinese content regulations, and you will not know which answers have been altered.

The larger question DeepSeek raises — whether the compute assumptions underlying American AI investment are correct — remains open. The answer will determine more about the AI industry's next five years than any single benchmark.

What is not settled, and what no amount of benchmark comparison resolves, is whether the efficiency gap between DeepSeek and its Western counterparts will narrow, hold, or widen. DeepSeek has continued releasing updated versions, the most recent being V3.2 and R1-0528. Western labs have begun adopting some of the same architectural innovations. The CSIS analysis of the export control question found that chip restrictions imposed real costs on DeepSeek — requiring two to four times the compute to match H100-based training runs — but did not stop the work. If DeepSeek achieves its planned chip independence, the constraint that forced the efficiency innovations disappears, and we will learn whether the architecture was a response to scarcity or a genuine preference.


What is DeepSeek and why did it shock Silicon Valley?

DeepSeek is a Chinese AI company, founded in 2023 as a subsidiary of the hedge fund High-Flyer, that released models in January 2025 claiming frontier AI performance at a fraction of Western training costs. The shock came from the $5.6 million training cost claim — compared to the hundreds of millions U.S. labs spend — which challenged the core investment thesis behind the AI hardware boom and wiped $589 billion from Nvidia's market capitalization in a single trading session.

Did DeepSeek really train its AI for only $6 million?

No, not in any complete sense. The $5.6 million figure covered GPU pre-training compute costs only — one training run on H800 chips. SemiAnalysis estimated DeepSeek's total server capital expenditure at $1.3 to $1.6 billion, with $944 million in operating costs. Google DeepMind's Demis Hassabis called the figure "exaggerated and misleading," noting it omitted the full R&D investment behind the model.

Is DeepSeek safe to use?

It depends on what you're using it for and how. The hosted service stores data on servers in China, where companies are legally required to provide government access without the right to refuse. In January 2025, a misconfigured database exposed over a million user chat logs and API keys publicly. Self-hosting the open-weight model eliminates the data risk. For sensitive data, government work, or regulated industries, the hosted service is not appropriate.

Does DeepSeek censor political topics?

Yes. DeepSeek's hosted chatbot declines to discuss or alters responses on topics Chinese authorities treat as sensitive — Tiananmen Square, Taiwan sovereignty, Xinjiang, and criticism of the Chinese government. The U.S. House Select Committee on the CCP found approximately 85% of politically sensitive topics it tested were suppressed or altered. This censorship applies to the hosted service; self-hosting the open weights removes inference-level filtering.

How does DeepSeek R1 compare to GPT-4o and Claude?

R1 matches or slightly trails frontier Western models on most benchmarks, while costing 5 to 10 times less per token. On mathematics and reasoning tasks, including AIME and MATH-500, R1 is competitive with OpenAI's o1. On agentic coding (SWE-bench Verified), Claude leads at 80.9%, DeepSeek at 78%, GPT-4 at 72%. On creative writing and nuanced instruction-following, DeepSeek trails meaningfully.

Did DeepSeek steal from OpenAI?

OpenAI alleged in a formal memo to Congress that DeepSeek used distillation — querying OpenAI's models at scale via third-party proxy accounts and using the outputs as training data. One analysis found 74.2% stylistic similarity between DeepSeek and ChatGPT outputs. DeepSeek denied the allegations. The legal question is unresolved: OpenAI's own terms assign output ownership to users, not to OpenAI, complicating any copyright claim.

What is Mixture-of-Experts and why does it matter for DeepSeek?

Mixture-of-Experts is an architecture where a model routes each input token through a small subset of specialist networks rather than activating all parameters. DeepSeek V3 carries 671 billion total parameters but activates only 37 billion per token — 5.5% of the model doing 100% of the work on each inference step. This reduces compute cost dramatically compared to a dense model of equivalent total size, enabling frontier-level performance at a fraction of the inference cost.

Should developers use DeepSeek instead of GPT-4 or Claude?

For cost-sensitive technical tasks involving non-sensitive data, DeepSeek's API pricing makes it difficult to ignore — roughly $1.10 per million output tokens versus $60 for OpenAI's o1. For tasks requiring agentic coding, creative writing, or politically neutral information, Western models maintain advantages. For any work involving legally protected data, regulated industries, or sensitive research, DeepSeek's hosted service is not appropriate regardless of pricing.

We welcome your analysis! Share your insights on the future trends discussed, or offer your expert perspective on this topic below.

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