GLM-5.1 (Reasoning) vs Mercury 2
Which is better for the money: GLM-5.1 (Reasoning) by Z AI or Mercury 2 by Inception? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-24.
Trade-off
Verdict
Depends on your budget
GLM-5.1 (Reasoning) scores 15.3 points higher (26.1 vs 10.8) but costs 14× as much to run the benchmark ($1487 vs $105; premium vs mid-range cost classes). They are not alternatives at one budget: pick GLM-5.1 (Reasoning) when you need intelligence above 10.8, and Mercury 2 when 10.8 is enough.
| Metric | GLM-5.1 (Reasoning) | Mercury 2 | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 26.1 | 10.8 | −58.6% Mercury 2 is 58.6% less intelligent |
| Total AA cost (lower is better) | $1,486.78 | $104.94 | −92.9% Mercury 2 is 92.9% cheaper |
| End-to-end time (lower is better) | 63.24s | 8.08s | −87.2% Mercury 2 is 87.2% faster |
| Price per 1M tokens (in / out) | $1.28 / $4.07 | $0.25 / $0.75 | |
| Input modalities | Text | Text |
Mercury 2 vs GLM-5.1 (Reasoning): 58.6% less intelligence, 92.9% less cost to run the AA benchmark, and 87.2% faster end-to-end.
Today's Pareto frontier
Against the frontier
- GLM-5.1 (Reasoning) is off the frontier: at the same or lower cost, GPT-6.1 Sol (Max) scores 51.80 for $1082.
- Mercury 2 is off the frontier: at the same or lower cost, Claude Haiku 5.5 (High) scores 37.80 for $94.1.
GLM-5.1 (Reasoning)Mercury 2Today's Pareto frontierOpen-weights frontierEvery other model
Matchup
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