Grok 4.1 Fast vs Grok 4 Fast Reasoning vs GLM-4.6V-Flash
Grok 4 Fast Reasoning comes out ahead, 75 to 66 and 63 on our weighted score, though GLM-4.6V-Flash is 5% cheaper per token.
xAIGrok 4.1 Fast
66/100- ECI—
- Price$0.20 / $0.50
- Context2M
- Our pickxAI
Grok 4 Fast Reasoning
75/100- ECI—
- Price$0.20 / $0.50
- Context2M
Z.ai (Zhipu)GLM-4.6V-Flash
63/100- ECI—
- Price$0.161 / $0.559
- Context128K
Grok 4 Fast Reasoning is our pick
Grok 4 Fast Reasoning is the better all-round choice, scoring 75/100 against Grok 4.1 Fast (66) and GLM-4.6V-Flash (63). It leads on inputs & features. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
- CapabilityNot enough dataNo independent benchmark covers every model here yet
- Lowest priceGLM-4.6V-FlashGLM-4.6V-Flash $0.261 · Grok 4.1 Fast $0.275 · Grok 4 Fast Reasoning $0.275 per 1M tokens (3:1 blend)
- Longest contextGrok 4.1 Fast and Grok 4 Fast ReasoningGrok 4.1 Fast 2,000,000 · Grok 4 Fast Reasoning 2,000,000 · GLM-4.6V-Flash 128,000 tokens
- Widest inputsGrok 4 Fast ReasoningGrok 4.1 Fast: Text, Images · Grok 4 Fast Reasoning: Text, Images, Audio, Video · GLM-4.6V-Flash: Text, Images, Video
- Self-hostingGLM-4.6V-FlashPublishes downloadable weights
| Measure | Weight | Grok 4.1 Fast | Grok 4 Fast Reasoning | GLM-4.6V-Flash |
|---|---|---|---|---|
| Price | 50% | 73 | 73 | 74 |
| Inputs & features | 30% | 50 | 80 | 70 |
| Context window | 20% | 72 | 72 | 24 |
| Overall | 100% | 66/100 | 75/100 | 63/100 |
Left out because at least one model lacks the data: capability. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Grok 4.1 FastxAI | Grok 4 Fast ReasoningxAI | GLM-4.6V-FlashZ.ai (Zhipu) |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | — | — | — |
| ECI rank | — | — | — |
| Price per million tokens | |||
| Input | $0.20 | $0.20 | $0.161 (best) |
| Output | $0.50 (best) | $0.50 (best) | $0.559 |
| Cached input | — | — | — |
| Blended (3:1) | $0.275 | $0.275 | $0.261 (best) |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Median of 6 providers | Median of 4 providers | Median of 2 providers |
| Limits | |||
| Context window | 2,000,000 tokens (best) | 2,000,000 tokens (best) | 128,000 tokens |
| Max output | 30,000 tokens | 2,000,000 tokens (best) | 32,768 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | No | No | No |
| Audio | No | Yes | No |
| Video | No | Yes | Yes |
| Reasoning | No | Yes | Yes |
| Tool calling | Yes | Yes | Yes |
| Structured output | No | No | No |
| Availability | |||
| Weights | Proprietary | Proprietary | Open |
| API model ID | — | — | glm-4.6v-flash |
| API providers | 8 (best) | 5 | 6 |
| Released | Nov 19, 2025 | Dec 18, 2025 | Dec 8, 2025 |
| Knowledge cutoff | — | — | — |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Grok 4.1 Fast$3.00
- Grok 4 Fast Reasoning$3.00
- GLM-4.6V-Flash$2.73
Which should you choose?
Which is better: Grok 4.1 Fast, Grok 4 Fast Reasoning or GLM-4.6V-Flash?
Grok 4 Fast Reasoning is the better all-round choice, scoring 75/100 against Grok 4.1 Fast (66) and GLM-4.6V-Flash (63). It leads on inputs & features. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
Which is cheaper, Grok 4.1 Fast, Grok 4 Fast Reasoning or GLM-4.6V-Flash?
GLM-4.6V-Flash is cheaper at $0.161 input / $0.559 output per million tokens (median across 2 API providers; free on Z.AI). Grok 4.1 Fast costs $0.20 input / $0.50 output per million tokens (median across 6 API providers); Grok 4 Fast Reasoning costs $0.20 input / $0.50 output per million tokens (median across 4 API providers). At a typical mix of three input tokens to one output token, that is $0.261 per million tokens for GLM-4.6V-Flash versus $0.275 for Grok 4.1 Fast (1.1× as much) and $0.275 for Grok 4 Fast Reasoning (1.1× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers all three models yet. Grok 4.1 Fast has not been scored yet, Grok 4 Fast Reasoning has not been scored yet and GLM-4.6V-Flash has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Grok 4.1 Fast, Grok 4 Fast Reasoning and GLM-4.6V-Flash yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. All three support tool calling for agent workflows.
Which has the bigger context window?
Grok 4.1 Fast and Grok 4 Fast Reasoning have the largest context windows (2,000,000 and 2,000,000 tokens), against 128,000 for GLM-4.6V-Flash. Maximum output per response: Grok 4.1 Fast up to 30,000, Grok 4 Fast Reasoning up to 2,000,000, GLM-4.6V-Flash up to 32,768 tokens.
Which can read images, PDFs, audio or video?
Grok 4.1 Fast accepts text and images; Grok 4 Fast Reasoning accepts text, images, audio and video; GLM-4.6V-Flash accepts text, images and video. Grok 4 Fast Reasoning handles the widest range of inputs.
Are any of these open source?
GLM-4.6V-Flash publishes its weights and can be self-hosted; Grok 4.1 Fast and Grok 4 Fast Reasoning is proprietary.
Which is newer?
Grok 4 Fast Reasoning is the newest, released Dec 18, 2025. GLM-4.6V-Flash came out Dec 8, 2025; Grok 4.1 Fast came out Nov 19, 2025.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.
