Knowledge
Directional only- Grok 4.1 Fast
- 40.6
- Estimated · #130/183
- Grok 4.20
- 49.4
- Supported · #85/183
- Basis
- BenchAlign lane · 0 vs 6 public rows
- Reading
- Directional only
Grok 4.1 Fast vs Grok 4.20
Updated September 10, 2026. Public scores include evidence status and uncertainty. They are not guarantees for a specific workload.
Decision reading
Grok 4.20 has the higher public score estimate, 67.13 versus 47.26, but the 90% score intervals overlap. Treat that as a lead, not a settled winner.
1 results are shared. Category rows resting on Estimated evidence or different benchmark sets are marked directional and do not name a winner.
Share or export
Which one for your work
Recommendations appear only when a shared evidence basis or an explicit operating constraint supports the call. Secondary and unsupported use cases stay disclosed below the initial list.
Chat turn cost
1K fresh input + 500 output tokens
Grok 4.1 Fast
Grok 4.1 Fast has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.
Confidence: listed-rates
Cache-heavy agent loop cost
200K cached + 20K fresh input + 10K output tokens
Grok 4.1 Fast
Grok 4.1 Fast has the lower estimated token cost for this stated workload. Grok 4.1 Fast has no published cached-input rate, so cached tokens use its listed input rate. Grok 4.20 has no published cached-input rate, so cached tokens use its listed input rate.
Confidence: rate-fallback
Show secondary and unsupported calls
Repository review cost
50K fresh input + 3K output tokens
Grok 4.1 Fast
Grok 4.1 Fast has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.
Confidence: listed-rates
Coding work
Code generation, repair, and software-engineering tasks
Not enough matched evidence
Grok 4.1 Fast is not ranked on the public lane for coding, so no winner is named for coding.
Confidence: limited
Agentic work
Tool use, computer use, and multi-step task completion
Not enough matched evidence
Grok 4.1 Fast is not ranked on the public lane for agentic, so no winner is named for agentic.
Confidence: limited
Long documents
Prompts that approach the documented context limit
No clear pick
The documented context windows are equal.
Confidence: documented
What is actually comparable
Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.
1 Shared
22 Grok 4.20 only
- Shared results
- 1
- Grok 4.1 Fast only
- 0
- Grok 4.20 only
- 22
- Like-for-like categories
- 0 / 8
1 category rests on Estimated evidence or different evidence sets. Those rows remain visible for coverage context but do not name a winner.
Category results, on a stated basis
Each row shows the public-lane category score for both models: the BenchAlign lane for agentic, coding, and knowledge, and the weighted public rows elsewhere, with the same rank each model page reports. A row is like-for-like only when both scores rest on Supported evidence or the same weighted set. Directional and not-comparable rows remain visible, but they never receive a winner.
Agentic
Not comparable- Grok 4.1 Fast
- Not ranked
- Grok 4.20
- 26.7
- Supported · #145/152
- Basis
- BenchAlign lane · 1 vs 4 public rows
- Reading
- Not comparable
Coding
Not comparable- Grok 4.1 Fast
- Not ranked
- Grok 4.20
- 28.2
- Supported · #141/151
- Basis
- BenchAlign lane · 0 vs 6 public rows
- Reading
- Not comparable
Reasoning
Not comparable- Grok 4.1 Fast
- 42.5
- Unranked · 2 rankable rows
- Grok 4.20
- 34.2
- Unranked · 2 rankable rows
- Basis
- Provisional lane · 0 vs 2 weighted rows
- Reading
- Not comparable
Math
Not comparable- Grok 4.1 Fast
- Not ranked
- Grok 4.20
- Not ranked
- Basis
- Provisional lane · 0 vs 0 weighted rows
- Reading
- Not comparable
Multilingual
Not comparable- Grok 4.1 Fast
- Not ranked
- Grok 4.20
- Not ranked
- Basis
- Provisional lane · 0 vs 0 weighted rows
- Reading
- Not comparable
Multimodal
Not comparable- Grok 4.1 Fast
- 31.3
- Unranked · 1 rankable row
- Grok 4.20
- 34.6
- #43/48
- Basis
- Provisional lane · 0 vs 2 weighted rows
- Reading
- Not comparable
Instruction following
Not comparable- Grok 4.1 Fast
- 42.1
- #101/123
- Grok 4.20
- Not ranked
- Basis
- Provisional lane · 0 vs 0 weighted rows
- Reading
- Not comparable
| Category | Grok 4.1 Fast | Grok 4.20 | Basis | Reading |
|---|---|---|---|---|
| Knowledge | 40.6Estimated · #130/183 | 49.4Supported · #85/183 | Directional onlyBenchAlign lane · 0 vs 6 public rows | Directional only |
| Agentic | Not ranked | 26.7Supported · #145/152 | Not comparableBenchAlign lane · 1 vs 4 public rows | Not comparable |
| Coding | Not ranked | 28.2Supported · #141/151 | Not comparableBenchAlign lane · 0 vs 6 public rows | Not comparable |
| Reasoning | 42.5Unranked · 2 rankable rows | 34.2Unranked · 2 rankable rows | Not comparableProvisional lane · 0 vs 2 weighted rows | Not comparable |
| Math | Not ranked | Not ranked | Not comparableProvisional lane · 0 vs 0 weighted rows | Not comparable |
| Multilingual | Not ranked | Not ranked | Not comparableProvisional lane · 0 vs 0 weighted rows | Not comparable |
| Multimodal | 31.3Unranked · 1 rankable row | 34.6#43/48 | Not comparableProvisional lane · 0 vs 2 weighted rows | Not comparable |
| Instruction following | 42.1#101/123 | Not ranked | Not comparableProvisional lane · 0 vs 0 weighted rows | Not comparable |
Ranks count the models scored in each category’s lane, so the agentic, coding, and knowledge denominators (BenchAlign) differ from the provisional-lane categories. Unranked scores sit on the lane’s scale but never name a winner. Like-for-like rows within 0.5 points read as a practical tie.
Shape of the matched evidence
Only shared public evidence is shown. Sparse evidence stays a ruled list rather than being closed into a radar shape.
A shared-evidence shape is not available.
BenchLM does not draw a radar or infer missing axes when the matched evidence is too sparse.
What each workload costs
Three fixed token mixes turn per-token rates into comparable decisions. Each scenario states context fit and whether cached input had to fall back to the published list-input rate.
Chat turn
1K fresh input + 500 output tokens
- Grok 4.1 Fast
- $0.00045
- Fits in one request
- Grok 4.20
- $0.005
- Fits in one request
Grok 4.1 Fast has the lower modeled cost
Costs use the listed standard API rates.
Repository review
50K fresh input + 3K output tokens
- Grok 4.1 Fast
- $0.0115
- Fits in one request
- Grok 4.20
- $0.118
- Fits in one request
Grok 4.1 Fast has the lower modeled cost
Costs use the listed standard API rates.
Cache-heavy agent loop
200K cached + 20K fresh input + 10K output tokens
- Grok 4.1 Fast
- $0.049
- Fits in one request
- Cached input priced at the published list-input rate
- Grok 4.20
- $0.5
- Fits in one request
- Cached input priced at the published list-input rate
Grok 4.1 Fast has the lower modeled cost
Grok 4.1 Fast has no published cached-input rate, so cached tokens use its listed input rate. Grok 4.20 has no published cached-input rate, so cached tokens use its listed input rate.
Specification differences
Sourced differences are shown directly. Missing facts stay explicit instead of being inferred from a model name or family.
SpecificationGrok 4.1 FastGrok 4.20
Context window
Maximum documented context; output-token limits may be lower.
Grok 4.1 Fast
2M
Grok 4.20
2M
API model ID
Grok 4.1 Fast
Not sourced
Grok 4.20
Not sourced
Cached-input rate
A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.
Grok 4.1 Fast
Not published
Grok 4.20
Not published
Documented inputs
Grok 4.1 Fast
Not sourced
Grok 4.20
Not sourced
Documented outputs
Grok 4.1 Fast
Not sourced
Grok 4.20
Not sourced
Provider availability
Grok 4.1 Fast
Not sourced
Grok 4.20
Not sourced
Reasoning profile
Grok 4.1 Fast
Non-Reasoning
Grok 4.20
Reasoning
Weight access
Grok 4.1 Fast
Proprietary
Grok 4.20
Proprietary
License
Grok 4.1 Fast
Proprietary
Grok 4.20
Proprietary
Release date
Grok 4.1 Fast
2025-11-19
Grok 4.20
2026-03-10
If you already use one of these models
- Deployment change
- Both entries list xAI as the provider. Confirm endpoint, model ID, limits, and feature support before switching.
- Quality signal
- Grok 4.20 has the higher public score estimate, 67.13 versus 47.26, but the 90% score intervals overlap.
- Workload cost
- Repository review: $0.0115 vs $0.118. Cache-heavy agent loop: $0.049 vs $0.5.
- Context tradeoff
- Both models list 2M.
Run the same representative tasks against both endpoints before changing production traffic.
Benchmark evidence
The full public result ledger is available for audit without forcing a wide desktop table onto a phone.
Browse raw public benchmark evidence23 rows
Agentic
Gert Labs
Shared sourceGrok 4.1 Fast47.32%Grok 4.2038.36%Grok 4.1 Fast leads this result
Terminal-Bench 2.0
Grok 4.1 Fast—Grok 4.2047.1%SourceNot directly comparable
DeepSearchQA
Grok 4.1 Fast—Grok 4.2062.8%SourceNot directly comparable
Terminal-Bench 2.1 (Vals)
Grok 4.1 Fast—Grok 4.2044.2%SourceNot directly comparable
Coding
LiveCodeBench Pro
Grok 4.1 Fast—Grok 4.2074.2%SourceNot directly comparable
SWE-bench Verified
Grok 4.1 Fast—Grok 4.2076.7%SourceNot directly comparable
SWE-bench Pro
Grok 4.1 Fast—Grok 4.2051.8%SourceNot directly comparable
Vibe Code Bench
Grok 4.1 Fast—Grok 4.204.06%SourceNot directly comparable
LiveCodeBench (Vals)
Grok 4.1 Fast—Grok 4.2084.3%SourceNot directly comparable
SWE-bench (Vals)
Grok 4.1 Fast—Grok 4.2072.2%SourceNot directly comparable
Reasoning
Knowledge
GPQA-D
Grok 4.1 Fast—Grok 4.2088.5%SourceNot directly comparable
HLE w/o tools
Grok 4.1 Fast—Grok 4.2031.6%SourceNot directly comparable
HealthBench Hard
Grok 4.1 Fast—Grok 4.2020.3%SourceNot directly comparable
MedXpertQA (Text)
Grok 4.1 Fast—Grok 4.2050.2%SourceNot directly comparable
GPQA Diamond (Vals)
Grok 4.1 Fast—Grok 4.2088.6%SourceNot directly comparable
MMLU-Pro (Vals)
Grok 4.1 Fast—Grok 4.2086.3%SourceNot directly comparable
Multimodal
MMMU-Pro
Grok 4.1 Fast—Grok 4.2075.2%SourceNot directly comparable
CharXiv
Grok 4.1 Fast—Grok 4.2060.9%SourceNot directly comparable
ERQA
Grok 4.1 Fast—Grok 4.2054.1%SourceNot directly comparable
SimpleVQA
Grok 4.1 Fast—Grok 4.2057.4%SourceNot directly comparable
MedXpertQA (MM)
Grok 4.1 Fast—Grok 4.2065.8%SourceNot directly comparable
Frequently asked questions
Which is better, Grok 4.1 Fast or Grok 4.20?
Grok 4.20 has the higher public score estimate, 67.13 versus 47.26, but the 90% score intervals overlap. The higher estimate is not a decisive winner because the uncertainty ranges overlap.
Which is better for coding, Grok 4.1 Fast or Grok 4.20?
Grok 4.1 Fast is not ranked on the public lane for coding, so no winner is named for coding.
Which is better for agentic tasks, Grok 4.1 Fast or Grok 4.20?
Grok 4.1 Fast is not ranked on the public lane for agentic tasks, so no winner is named for agentic tasks.
Which costs less, Grok 4.1 Fast or Grok 4.20?
For the stated presets, chat costs $0.00045 on Grok 4.1 Fast and $0.005 on Grok 4.20; repository review costs $0.0115 and $0.118; the cache-heavy agent loop costs $0.049 and $0.5. Grok 4.1 Fast has no published cached-input rate, so cached tokens use its listed input rate. Grok 4.20 has no published cached-input rate, so cached tokens use its listed input rate.
Which has the larger context window, Grok 4.1 Fast or Grok 4.20?
Both models list the same context window, 2M.
Related comparisons
Last updated September 10, 2026
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