Curiosity · AI Model
Grok 1.5
Grok 1.5 was xAI's first substantial update to its flagship LLM, released in March 2024 to X Premium subscribers and early-access partners. Compared with the open-sourced Grok-1 (314B MoE), Grok 1.5 was a from-scratch retraining focused on reasoning and long-context — extending the context window to 128k tokens and delivering large jumps on MATH, GSM8K, and HumanEval. A vision variant (Grok 1.5V) followed in April 2024, adding real-world reasoning over images.
Model specs
- Vendor
- xAI
- Family
- Grok
- Released
- 2024-03
- Context window
- 128,000 tokens
- Modalities
- text, vision
Strengths
- Big reasoning jump over Grok-1
- 128k context was competitive at 2024 release
- Introduced xAI's vision capability (Grok 1.5V)
- Powered the Grok chat experience on X during 2024
Limitations
- Fully superseded — Grok 2, 3, and 4 all beat it
- Not offered on current xAI API
- No open weights (unlike Grok-1)
- Safety tuning weaker than contemporaries
Use cases
- Historical reference for Grok-series progression
- X (Twitter) chat during 2024
- Benchmarking long-context LLMs at 128k
- Vision variant (Grok 1.5V) — early xAI multimodal pilot
Benchmarks
| Benchmark | Score | As of |
|---|---|---|
| MATH | ≈50% | 2024-03 |
| GSM8K | ≈90% | 2024-03 |
| HumanEval | ≈74% | 2024-03 |
Frequently asked questions
What is Grok 1.5?
Grok 1.5 is xAI's March 2024 update over Grok-1 — a retrained LLM with 128k context and substantially stronger reasoning, math, and code benchmarks.
Is Grok 1.5 open-source?
No — unlike the original Grok-1 (whose weights were released), Grok 1.5 was never open-sourced.
Should I use Grok 1.5 today?
No. Grok 2 and Grok 3/4 supersede it. Grok 1.5 is primarily a historical reference point.
Sources
- xAI — Announcing Grok 1.5 — accessed 2026-04-20
- xAI — Grok 1.5V vision — accessed 2026-04-20