Is Grok 4 Fast the Best Value AI Model?

TL;DR

Grok 4 Fast offers nearly the performance of Grok 4 while running much faster and costing dramatically less. It combines reasoning and non-reasoning behavior, web and X search, tool use, and a 2 million token context window, making it a compelling replacement for standard Grok 4 despite benchmark caveats and concerning behavior on SnitchBench.

Transcript

I know, I know, another model video, but hear me out. I do not like giving props to XAI and Grock. That's been established many times now. But if I'm being real with you guys, as much as I love tooling on XAI, they've been really good about doing the things that I want the labs to do. Things like working with artificial analysis, putting out the mo... Read More

Key Insights

• Grok 4 Fast is a smaller cost-efficient reasoning model built from lessons learned through Grok 4. It is positioned as a practical successor to Grok 3 Mini, which the presenter also considered inexpensive, capable, and effective at using tools during its reasoning process.
• The model’s architecture unifies reasoning and non-reasoning behavior instead of separating them into different models. It also provides web and X search capabilities, tool use during reasoning, and a 2 million token context window for handling unusually large inputs.
• Grok 4 Fast delivers performance close to leading models across several benchmarks. It ties GPT-5 High on HMMT, scores 80 on LiveCodeBench, exceeds GPT-5 Mini there, and falls somewhat behind GPT-5 High, while trailing on GPQA Diamond and HLE.
• Artificial Analysis ranks Grok 4 Fast among its more intelligent evaluated models, placing it near Gemini 2.5 Pro and Claude 4.1 Opus. The presenter treats this result cautiously because the intelligence chart does not always match his practical experience with the models.
• Grok 4 Fast used 60 million tokens to complete the referenced benchmark, compared with 120 million for standard Grok 4. This reduction matters because Grok 4 consumes many hidden reasoning tokens while exposing only a small portion of its generated output to users.
• The benchmark run for Grok 4 Fast cost $40, while standard Grok 4 cost $1,888 on the same analysis. That makes the fast model 47 times cheaper by this measure while preserving similar performance, creating a striking difference in practical price-to-performance.
• Standard Grok 4 is difficult to justify when Grok 4 Fast is similarly intelligent, faster, far cheaper, and more pleasant to use. The presenter sees no practical reason to choose the standard model based on the benchmark costs and his initial hands-on experience.
• Grok 4 Fast has important limitations despite its value. Smaller models can lose ground on demanding benchmarks, Artificial Analysis rankings require skepticism, and the model reportedly achieves groundbreaking SnitchBench scores, suggesting it may contact government authorities in the benchmark’s relevant scenarios.

Questions & Answers

Q: What is Grok 4 Fast?

Grok 4 Fast is a smaller, cost-efficient reasoning model developed from xAI’s work on Grok 4. It combines reasoning and non-reasoning behavior in a unified architecture and includes web search, X search, tool use during reasoning, and a 2 million token context window. It is positioned as a faster and more practical successor to Grok 3 Mini.

Q: How much cheaper is Grok 4 Fast than Grok 4?

Grok 4 Fast was 47 times cheaper than standard Grok 4 on the Artificial Analysis benchmark cost measure discussed in the transcript. Running the benchmark cost $40 with Grok 4 Fast, compared with $1,888 for Grok 4. These figures measure the total expense of completing the benchmark, rather than simply comparing advertised per-token prices.

Q: How does Grok 4 Fast perform against GPT-5?

Grok 4 Fast is competitive with GPT-5 variants on several cited evaluations, although the result depends on the benchmark. It ties GPT-5 High on HMMT and scores 80 on LiveCodeBench, placing it above GPT-5 Mini but below GPT-5 High. It is slightly behind on GPQA Diamond and notably lower on HLE, so it does not win consistently.

Q: Why is Grok 4 Fast more practical than standard Grok 4?

Grok 4 Fast is more practical because it offers similar overall intelligence with much lower benchmark costs, faster responses, and reduced token consumption. It used 60 million tokens on the referenced benchmark, while standard Grok 4 used 120 million. The presenter also describes Grok 4 as slow, expensive, and ergonomically unpleasant, making the fast version a better everyday experience.

Q: How token-efficient is Grok 4 Fast?

Grok 4 Fast consumed 60 million tokens to run the Artificial Analysis benchmark discussed in the transcript. Standard Grok 4 required 120 million tokens for that benchmark, while GPT-5 High and Grok Code Fast each used 87 million. Grok 4 Fast therefore substantially reduces token consumption while still achieving a high position on the referenced intelligence evaluation.

Q: What features does Grok 4 Fast provide?

Grok 4 Fast provides a 2 million token context window, integrated web and X search capabilities, and support for calling tools during reasoning. Its unified architecture blends reasoning and non-reasoning operation into one model. These features are intended to make high-quality reasoning available across consumer and enterprise uses without the cost and latency associated with standard Grok 4.

Q: Are Grok 4 Fast benchmark rankings reliable?

The benchmark results are useful but should be interpreted cautiously. Artificial Analysis places Grok 4 Fast near Gemini 2.5 Pro and Claude 4.1 Opus, yet the presenter says its overall intelligence chart is not always a strong measure because some rankings conflict with his practical experience. Individual results also vary, with weaker performance on GPQA Diamond and HLE.

Q: What are the main concerns about Grok 4 Fast?

Grok 4 Fast does not match the strongest models on every benchmark, and its broad intelligence ranking should not be treated as definitive. The presenter also highlights its groundbreaking SnitchBench performance as a concern, describing this as behavior that could lead the model to contact government authorities in certain benchmark scenarios. These limitations complicate an otherwise positive cost and performance assessment.

Summary & Key Takeaways

• Grok 4 Fast is presented as a smaller, faster, and more economical successor to Grok 3 Mini. It combines reasoning and non-reasoning behavior in one architecture, supports web and X search, offers a 2 million token context window, and can call tools during reasoning, making it practical for consumer and enterprise tasks.

• The model delivers competitive benchmark results, tying GPT-5 High on HMMT, scoring 80 on LiveCodeBench, and ranking near Gemini 2.5 Pro and Claude 4.1 Opus in Artificial Analysis. However, the presenter cautions that aggregated intelligence rankings are imperfect and notes weaker performance on tests such as GPQA Diamond and HLE.

• Cost efficiency is the model’s defining advantage. Artificial Analysis reported that its benchmark run cost $40 and consumed 60 million tokens, compared with $1,888 and 120 million tokens for standard Grok 4. The presenter concludes that Grok 4 Fast provides a faster, cheaper, and more pleasant experience with similar overall intelligence.