vs
15:1
overall capability wins (1 ties across 17 scored). GPT-5.6 Sol leads overall.
- Reasoning6:0
- Coding5:1
- Arena1:0
- Agents1:0
- Tool use1:0
- Composite indices2:0
- Pricing0:3
- Speed0:2
- Specs1:0
Verdict
GPT-5.6 Sol leads coding (widest gap: +62.2 on WebDev Elo); GPT-5.6 Sol ranks higher on LMArena (+15 Elo); GPT-5.6 Sol offers ~2.1x larger context (1.1M vs 500K).
- GPT-5.6 Sol leads coding (widest gap: +62.2 on WebDev Elo)
- GPT-5.6 Sol ranks higher on LMArena (+15 Elo)
- GPT-5.6 Sol offers ~2.1x larger context (1.1M vs 500K)
- Grok 4.5 is ~2.7x cheaper on a blended token basis than GPT-5.6 Sol
Cost for 1M in + 250K out
Illustrative chat workload at primary-provider list prices.
- GPT-5.6 Sol
- $9
- Grok 4.5
- $3.50
Grok 4.5 is about 2.6x cheaper on this workload.
Price per 1M tokens
Full comparison
Organization
OpenAI
xAI
Family
GPT-5.x
Grok
License
Proprietary
Proprietary
Open weights
No
No
Release
Jul 9, 2026
Jul 9, 2026
Knowledge cutoff
2026-02-16
-
API / provider
OpenAI
xAI
Modalities
text, image → text
text, image → text
Specs
Context window
1.1M
500K
Max output
128K
128K
Parameters
—
—
Pricing
Input $/1M
$4
$2
Output $/1M
$20
$6
Blended $/1M (3∶1)
$8
$3
Speed
tok/s
96
100
TTFT (s)
0.45
0.35
Reasoning
MMLU-Pro
—
—
GPQA Diamond
94.1
93.1
Humanity's Last Exam
49.5
42.7
AIME 2025
—
—
MATH-500
—
—
Humanity's Last Exam (with tools)
—
—
AA-Omniscience Accuracy
59.4
51.6
AA-LCR v1.1
84.0
79.3
CritPt
32.3
15.4
MMMU-Pro
83.4
80.4
IFBench
72.7
—
Chartography
—
—
Chartography (With Tools)
—
—
Coding
SWE-bench Verified
—
—
SWE-bench Pro
64.6
—
SWE-bench Multilingual
—
—
LiveCodeBench
—
—
Terminal-Bench 2.1
88.0
81.6
Aider Polyglot
—
—
Terminal-Bench 3
34.6
15.7
BigCodeBench
—
—
SciCode
57.1
55.0
CursorBench
67.2
—
SWE-Rebench
62.3
63.8
NL2Repo-Bench
—
—
DeepSWE
72.7
—
WebDev Arena
1,617
1,555
Terminal-Bench 4.0
37.3
12.4
CursorBench 4.0
—
—
FrontierCode v1.1 (Main)
—
—
Arena
LMArena Elo
1,484
1,468
| Metric | GPT-5.6 Sol | Grok 4.5 | Delta |
|---|---|---|---|
| Identity | |||
| Organization | OpenAI | xAI | — |
| Family | GPT-5.x | Grok | — |
| License | Proprietary | Proprietary | — |
| Open weights | No | No | — |
| Release | Jul 9, 2026 | Jul 9, 2026 | — |
| Knowledge cutoff | 2026-02-16 | - | — |
| API / provider | OpenAI | xAI | — |
| Modalities | text, image → text | text, image → text | — |
| Specs | |||
| Context window | 1.1M | 500K | A +550K |
| Max output | 128K | 128K | tie |
| Parameters | — | — | — |
| Pricing | |||
| Input $/1M | $4 | $2 | B +$2 |
| Output $/1M | $20 | $6 | B +$14 |
| Blended $/1M (3∶1) | $8 | $3 | B +$5 |
| Speed | |||
| tok/s | 96 | 100 | B +4.00 |
| TTFT (s) | 0.45 | 0.35 | B +0.10 |
| Reasoning | |||
| MMLU-Pro | — | — | — |
| GPQA Diamond | 94.1 | 93.1 | A +1.0 pts |
| Humanity's Last Exam | 49.5 | 42.7 | A +6.8 pts |
| AIME 2025 | — | — | — |
| MATH-500 | — | — | — |
| Humanity's Last Exam (with tools) | — | — | — |
| AA-Omniscience Accuracy | 59.4 | 51.6 | A +7.8 pts |
| AA-LCR v1.1 | 84.0 | 79.3 | A +4.7 pts |
| CritPt | 32.3 | 15.4 | A +16.9 pts |
| MMMU-Pro | 83.4 | 80.4 | A +3.0 pts |
| IFBench | 72.7 | — | — |
| Chartography | — | — | — |
| Chartography (With Tools) | — | — | — |
| Coding | |||
| SWE-bench Verified | — | — | — |
| SWE-bench Pro | 64.6 | — | — |
| SWE-bench Multilingual | — | — | — |
| LiveCodeBench | — | — | — |
| Terminal-Bench 2.1 | 88.0 | 81.6 | A +6.4 pts |
| Aider Polyglot | — | — | — |
| Terminal-Bench 3 | 34.6 | 15.7 | A +18.9 pts |
| BigCodeBench | — | — | — |
| SciCode | 57.1 | 55.0 | A +2.1 pts |
| CursorBench | 67.2 | — | — |
| SWE-Rebench | 62.3 | 63.8 | B +1.5 pts |
| NL2Repo-Bench | — | — | — |
| DeepSWE | 72.7 | — | — |
| WebDev Arena | 1,617 | 1,555 | A +62 Elo |
| Terminal-Bench 4.0 | 37.3 | 12.4 | A +24.9 pts |
| CursorBench 4.0 | — | — | — |
| FrontierCode v1.1 (Main) | — | — | — |
| Arena | |||
| LMArena Elo | 1,484 | 1,468 | A +15 Elo |
GPT-5.6 Sol
- Context
- 1.1M / 128K out
- Parameters
- —
- Price
- $4 / $20
- Speed
- 96 tok/s · 0.45s TTFT
- Modalities
- text, image → text
- License
- Proprietary
OpenAI's July 2026 flagship reasoning tier, tuned for hard STEM and agentic work; ChatGPT's top API SKU in the 5.6 family. Promotional Standard rates are $4/$20 (through at least Nov 21, 2026). Fast mode (2× price) delivers up to 2.5× Standard speed, and the Cerebras-powered Ultrafast preview reaches up to 750 tok/s.
Grok 4.5
- Context
- 500K / 128K out
- Parameters
- —
- Price
- $2 / $6
- Speed
- 100 tok/s · 0.35s TTFT
- Modalities
- text, image → text
- License
- Proprietary
xAI/SpaceXAI public API flagship (July 2026) - Cursor-trained coding focus at $2/$6. For the Cursor IDE jointly-trained SKU and Fast tier, see Cursor Grok 4.5.
Benchmark charts
Winner bars are emphasized. Per-benchmark deltas sit above each chart.