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© 2026 CompareLLM. Public benchmark data aggregated from Arena Elo, LiveBench, SWE-bench & OpenRouter.

Every score has a dated snapshot.

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  3. Anthropic: Claude Opus 4.8 (Fast) vs Grok 4

Pairwise benchmark snapshot · Aug 17, 2026noindex (thin pair)

Anthropic: Claude Opus 4.8 (Fast) vs Grok 4 benchmark

In this head-to-head showdown, Grok 4 is more budget-friendly at $15/1M per 1M output tokens. Review the complete breakdown below to determine which model best fits your performance and budget requirements.

Executive Comparison Verdict

Bottom Line: Choose Anthropic: Claude Opus 4.8 (Fast) if your priority is peak reasoning, complex code generation, and top preference Elo. Choose Grok 4 if you are optimizing for low latency, high throughput, and cost-efficient API deployment.
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Executive Verdict Summary

Grok 4 holds empirical advantage (2 of 3 metrics)

Coding / SWESWE-bench
Grok 4Top code solve rate
ReasoningGPQA / Live
Grok 4Top logical accuracy
Best Value$/1M Tok
Grok 4Lowest API billing cost
Speed / TokTok/Sec
Grok 4Fastest stream rate

Verified Advantage Breakdown

3 benchmarks evaluated across capability, speed, and cost

Anthropic: Claude Opus 4.8 (Fast) (1)Grok 4 (2)
Anthropic: Claude Opus 4.8 (Fast)
1 of 3 Wins
✓Context window
Grok 4
2 of 3 Wins
✓Input price✓Output price
Anthropic
Leads 1 of 3
Anthropic: Claude Opus 4.8 (Fast)

Auto-discovered from OpenRouter (anthropic/claude-opus-4.8-fast). Preview until a second source matches.

In: $10 · Out: $50/1M
xAI
Leads 2 of 3
Grok 4

Previous xAI flagship.

Grok 4.0Elo 1,488In: $3 · Out: $15/1M
Top Rival Showdowns for Anthropic: Claude Opus 4.8 (Fast)
All Matchups
Compare vs:vs GPT-5vs Gemini 3 Provs Grok 4.6vs DeepSeek V4 Provs Qwen 3 Max
Preference Leader

No shared data

Single model data

Throughput Leader

No shared data

No latency data

Value per Dollar LeaderGrok 4 Wins

Grok 4

$15 / 1M output

Capability Percentiles

Relative percentile scores computed across all active models in the benchmark catalog.

Multi-Dimensional Capability Radar

Leaders Matchup Capability Radar

Comparing top standard models across 6 key capability dimensions. Tap any spoke or dot to inspect.

Tap any node to inspect
0–100 %ile

Overall Matchup Breakdown

Category wins across reasoning intelligence, generation speed, and token cost.

Anthropic: Claude Opus 4.8 (Fast) (1)vsGrok 4 (8)
Anthropic: Claude Opus 4.8 (Fast): 1W (11%)Overall: Grok 4Grok 4: 8W (89%)
← Anthropic: Claude Opus 4.8 (Fast)Grok 4 →
🏆Grok 4 Leads(4/5)

Intelligence & Reasoning

Preference Elo, Coding proficiency, SWE-bench & LiveBench accuracy

Benchmark
Anthropic: Claude Opus 4.8 (Fast)vsGrok 4
Preference Elo
—vs1,488
Coding Elo
—vs—
SWE-bench
—vs58.6%
LiveBench
—vs64.1%
GPQA Diamond
—vs79%
Anthropic: Claude Opus 4.8 (Fast): 0WGrok 4: 4W
🏆Grok 4 Leads(2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Benchmark
Anthropic: Claude Opus 4.8 (Fast)vsGrok 4
Output speed
—vs98 tok/s
Time to first token
—vs230 ms
Anthropic: Claude Opus 4.8 (Fast): 0WGrok 4: 2W
🏆Grok 4 Leads(2/3)

Pricing & Capacity

Cost per million tokens and max context window length

Benchmark
Anthropic: Claude Opus 4.8 (Fast)vsGrok 4
Output price
$50/1Mvs$15/1M+$35/1M
Input price
$10/1Mvs$3/1M+$7/1M
Context window
1Mvs256k+744k
Anthropic: Claude Opus 4.8 (Fast): 1WGrok 4: 2W

Side-by-Side Benchmark Matrix

Anthropic: Claude Opus 4.8 (Fast)Grok 4
Preference Elo
Anthropic: Claude Opus 4.8 (Fast)—
Grok 41,488
LiveBench
Anthropic: Claude Opus 4.8 (Fast)—
Grok 464.1%
SWE-bench
Anthropic: Claude Opus 4.8 (Fast)—
Grok 458.6%
GPQA Diamond
Anthropic: Claude Opus 4.8 (Fast)—
Grok 479%
Time to first token
Anthropic: Claude Opus 4.8 (Fast)—
Grok 4230 ms
Output speed
Anthropic: Claude Opus 4.8 (Fast)—
Grok 498 tok/s
Input priceGrok 4 +$7/1M
Anthropic: Claude Opus 4.8 (Fast)$10/1M
Grok 4$3/1M
Output priceGrok 4 +$35/1M
Anthropic: Claude Opus 4.8 (Fast)$50/1M
Grok 4$15/1M
Context windowAnthropic: Claude Opus 4.8 (Fast) +744k
Anthropic: Claude Opus 4.8 (Fast)1M
Grok 4256k
BenchmarkAnthropic: Claude Opus 4.8 (Fast)Grok 4Advantage Delta
Preference Elo—
1,488
lmarena · Aug 17, 2026
—
LiveBench—
64.1%
livebench · Aug 17, 2026
—
SWE-bench—
58.6%
swebench · Aug 17, 2026
—
GPQA Diamond—
79%
seed-bootstrap · Aug 1, 2026
—
Time to first token—
230 ms
seed-bootstrap · Aug 1, 2026
—
Output speed—
98 tok/s
seed-bootstrap · Aug 1, 2026
—
Input price
$10/1M
openrouter · Aug 17, 2026
$3/1M
seed-bootstrap · Aug 1, 2026
+$7/1M
Output price
$50/1M
openrouter · Aug 17, 2026
$15/1M
seed-bootstrap · Aug 1, 2026
+$35/1M
Context window
1M
openrouter · Aug 17, 2026
256k
seed-bootstrap · Aug 1, 2026
+744k

Workload Cost & Savings Calculator

Simulate monthly production API costs in USD (US Dollar).

Save 70% with Grok 4
Monthly Volume50M tokens/mo
Quick Presets:
Token Ratio (In vs Out)70% In / 30% Out
RAG / Search (10% out)Coding / Chat (50% out)
Anthropic: Claude Opus 4.8 (Fast)$1,100.00 / mo
In: $350Out: $750
Grok 4$330.00 / mo
In: $105Out: $225
Estimated Cost Delta

Grok 4 is estimated to save $770.00/month ($9,240/year).

Based on 50M tokens (30% gen)

Key Selection Recommendations

  • 1
    Grok 4:Pick Grok 4 when you are optimizing output cost.
  • 2
    Anthropic: Claude Opus 4.8 (Fast):Pick Anthropic: Claude Opus 4.8 (Fast) for million-token RAG or long-document jobs.

Recommended Workload Routing

Repo / coding agentsinsufficient data

Need SWE-bench on both sides.

High-volume chatGrok 4

Lower output list price ($15/1M).

Voice / low-latency UIinsufficient data

Need TTFT on both sides.

Long-document RAGAnthropic: Claude Opus 4.8 (Fast)

Larger window (1M).

Screenshots / visionGrok 4

Grok 4 is the side marked multimodal in the catalog.

Target WorkloadRecommended PickEvaluation Rationale
Repo / coding agentsinsufficient dataNeed SWE-bench on both sides.
High-volume chatGrok 4Lower output list price ($15/1M).
Voice / low-latency UIinsufficient dataNeed TTFT on both sides.
Long-document RAGAnthropic: Claude Opus 4.8 (Fast)Larger window (1M).
Screenshots / visionGrok 4Grok 4 is the side marked multimodal in the catalog.

Related Editorial Dispatches & Benchmark Notes

View all news
launchJul 10, 2025

Grok 4 remains the previous xAI flagship on this catalog

2025-07 row. 4.6 is the buy. We keep 4 so upgrade pairs and old inbound links resolve.

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CompareLLM AI Matrix

Verified Head-to-Head Telemetry

LIVE BENCHMARK
VS
Anthropic

Anthropic: Claude Opus 4.8 (Fast)

Elo n/a
SWE-bench—
Speed (tok/s)1M
Input / 1M Tokens$10/1M
Output / 1M Tokens$50/1M
xAI

Grok 4

Elo 1,488
SWE-bench58.6%
Speed (tok/s)98 tok/s
Input / 1M Tokens$3/1M
Output / 1M Tokens$15/1M

Frequently Asked Questions

Which is better overall, Anthropic: Claude Opus 4.8 (Fast) or Grok 4?
We do not have preference Elo for both models, so we do not declare an overall winner. Compare the metrics that exist.
Which is better at coding, Anthropic: Claude Opus 4.8 (Fast) or Grok 4?
SWE-bench is missing for at least one model, so we do not rank coding from a single number.
Which is cheaper to run in production?
Grok 4 output tokens are $15/1M versus $50/1M. Input prices and retry rates still move the real bill.
Which is faster, Anthropic: Claude Opus 4.8 (Fast) or Grok 4?
We do not have TTFT for both models.
Which has the larger context window?
Anthropic: Claude Opus 4.8 (Fast) accepts 1M tokens versus 256k.
Can I self-host either model?
Neither model is marked open-weights here. You are comparing hosted APIs.
Are these scores from CompareLLM’s own evals?
No. V1 aggregates public leaderboards (and optional first-party latency pings). Each cell names its source and date. Read /methodology.
What does preference Elo mean on this page?
Preference Elo is a crowd vote from LMArena / Arena. People see two hidden answers and pick the one they like more. The model that wins more often gets a higher Elo. That means people preferred it — not that it passed a school test. It is not SWE-bench, not accuracy, and not a number we invent. Anthropic: Claude Opus 4.8 (Fast) and Grok 4 Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.

Related news

  • launch · Jul 10, 2025

    Grok 4 remains the previous xAI flagship on this catalog

Similar Head-to-Head Comparisons

All Anthropic: Claude Opus 4.8 (Fast) matchups →|All Grok 4 matchups →
Grok 4 vs Grok 3 (previous grok)Grok 4 vs Grok 4.6 (next grok)Claude Opus 4.5 vs Grok 4Claude Opus 4.6 vs Grok 4Claude Sonnet 4.5 vs Grok 4Claude Opus 5 vs Grok 4