Grok 4.6 vs Viv Fast
Viv Fast comes out ahead, 75 to 44 on our weighted score, and it is the cheaper option too.
Viv Fast is our pick
Viv Fast is the better all-round choice, scoring 75/100 against Grok 4.6 (44). It leads on price and context window. 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 priceViv FastViv Fast $0.198 · Grok 4.6 $3.00 per 1M tokens (3:1 blend)
- Longest contextViv FastViv Fast 1,000,000 · Grok 4.6 500,000 tokens
- Widest inputsSame inputsGrok 4.6: Text, Images · Viv Fast: Text, Images
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | Grok 4.6 | Viv Fast |
|---|---|---|---|
| Price | 50% | 27 | 83 |
| Inputs & features | 30% | 70 | 70 |
| Context window | 20% | 48 | 60 |
| Overall | 100% | 44/100 | 75/100 |
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 4.6xAI |  Viv FastVivgrid |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | 156.6 | — |
| ECI rank | #19 of 148 | — |
| GPQA DiamondGraduate-level science questions | 94.0% | — |
| FrontierMath Tiers 1–3Research-level mathematics | 66.0% | — |
| OTIS Mock AIME 2024–2025Competition mathematics | 99.2% | — |
| SimpleQA VerifiedShort factual questions | 49.3% | — |
| Price per million tokens | ||
| Input | $2.00 | $0.13 (best) |
| Output | $6.00 | $0.40 (best) |
| Cached input | $0.50 | $0.05 (best) |
| Blended (3:1) | $3.00 | $0.198 (best) |
| Long-context rate | Over 200K: $4.00 / $12.00 | Same rate |
| Price source | Official xAI API | Official Vivgrid API |
| Limits | ||
| Context window | 500,000 tokens | 1,000,000 tokens (best) |
| Max output | 500,000 tokens (best) | 256,000 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | Yes |
| PDFs | No | No |
| Audio | No | No |
| Video | No | No |
| Reasoning | Yeslow · medium · high · xhigh | Yeslow · high · max |
| Tool calling | Yes | Yes |
| Structured output | Yes | Yes |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | grok-4.6 | viv-fast |
| API providers | 29 (best) | 1 |
| Released | Aug 12, 2026 | Sep 21, 2026 |
| Knowledge cutoff | Feb 1, 2026 | Sep 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Grok 4.6$32.00
- Viv Fast$2.10
Which should you choose?
Which is better: Grok 4.6 or Viv Fast?
Viv Fast is the better all-round choice, scoring 75/100 against Grok 4.6 (44). It leads on price and context window. 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 4.6 or Viv Fast?
Viv Fast is cheaper at $0.13 input / $0.40 output per million tokens (official Vivgrid API price). Grok 4.6 costs $2.00 input / $6.00 output per million tokens (official xAI API price). At a typical mix of three input tokens to one output token, that is $0.198 per million tokens for Viv Fast versus $3.00 for Grok 4.6 (15× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. Grok 4.6 has an ECI of 156.6 and Viv Fast has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Grok 4.6 and Viv Fast yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.
Which has the bigger context window?
Viv Fast has the largest context window at 1,000,000 tokens, against 500,000 for Grok 4.6. Maximum output per response: Grok 4.6 up to 500,000, Viv Fast up to 256,000 tokens.
Which can read images, PDFs, audio or video?
Grok 4.6 accepts text and images; Viv Fast accepts text and images. They handle the same number of input types.
Are any of these open source?
No. Grok 4.6 and Viv Fast are proprietary and only available through APIs and apps.
Which is newer?
Viv Fast is the newest, released Sep 21, 2026. Grok 4.6 came out Aug 12, 2026. Knowledge cutoff: Grok 4.6 Feb 1, 2026, Viv Fast Sep 2026.
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 Oct 4, 2026.
