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GPT-5.6 Sol vs Qwen3.8 Max

vs

Which one, when — curated verdict, not a benchmark table

These two are close on shape — both take text and image in, return text, and carry chat, vision, code, tools and reasoning — so the split is mostly price and knobs: qwen3.8-max runs $2 input and $6 output against $5 and $30 for gpt-5.6-sol, making it 2.5x cheaper on input and 5x cheaper on output, with cache reads at $0.25 versus $0.5. Pick gpt-5.6-sol when you want the slightly larger 1050000-token context or the ability to turn thinking off for latency-sensitive calls; pick qwen3.8-max for high-volume work where its 983616-token window and 131072 max output are enough.

Pricing

GPT-5.6 Sol Qwen3.8 Max Δ
Input / 1M tokens $5 $2 2.5×
Output / 1M tokens $30 $6
Cache read / 1M tokens $0.5 $0.25
Cache write no separate charge 1.25x

Rates from the live catalog at build time; each model page carries the current card.

Where they sit — input price per 1M tokens across all 63 chat models on this billing unit (log scale)

GPT-5.6 Sol · $5 Qwen3.8 Max · $2
$0.05 · Qwen3 VL Flash $30 · GPT-5.4 Pro

Capabilities

GPT-5.6 Sol Qwen3.8 Max
Tool use yes yes
Thinking control configurable yes — vendor dial not published
Structured output yes yes
Prompt caching implicit (automatic) implicit + explicit
Cache lifetime 5–10m, up to 1h explicit: 5m, reset on hit
Minimum cached prefix 1024 tokens 1024 tokens

Specs

GPT-5.6 Sol Qwen3.8 Max
Input modalities text image text image
Output modalities text text
Released 2026-07-09 2026-08-03
Knowledge cutoff 2026-02
Context window 1.1M 984K
Max output 128K 131K
Thinking parameter reasoning.effort
Accepted values
reasoning.effort
  • none
  • low
  • medium
  • high
  • xhigh
  • max
Default medium

Specs are transcribed from each vendor’s documentation; a row a vendor does not publish is left out rather than inferred. Full sources: GPT-5.6 Sol · Qwen3.8 Max

One prompt, both models — measured through the gateway

PROMPT Explain to a CFO, in exactly three sentences, why our LLM bill doubled after we enabled reasoning. CHECK exactly 3 sentences

GPT-5.6 Sol passed · 3 sentences

Enabling reasoning makes the model generate additional internal tokens before producing an answer, so each request consumes more billable compute. Reasoning may also increase response length, latency, tool calls, and retries, further raising per-request cost. In short, usage volume may be unchanged, but the cost per task increased enough to double the bill.

out 111 tok (+34 thinking) latency 2.3 s

Qwen3.8 Max passed · 3 sentences

Enabling reasoning makes the model produce additional hidden steps before responding, and those tokens are billable. It also tends to lengthen each interaction because the model works through more possibilities before settling on an answer. Therefore, the bill doubled mainly due to higher compute and token usage per request, not necessarily because the number of requests doubled.

out 378 tok (+305 thinking) latency 8.6 s

Instruction following (exactly three sentences — countable), audience shaping (CFO register), and the hidden-thinking billing gap the token meters below expose.

PROMPT This function is supposed to return the longest run of consecutive equal items, but callers report it is off by one on single-element inputs and misses runs that end at the last index. Fix it and explain the bug in one paragraph. CHECK fix passes tests

GPT-5.6 Sol passed · 8/8 cases

```python def longest_run(xs): if not xs: return 0 best = cur = 1 for i in range(1, len(xs)): if xs[i] == xs[i - 1]: cur += 1 else: cur = 1 best = max(best, cur) return best ``` The original function counted equal *adjacencies* rather than items, so a run of length one produced `0` and every longer run was undercounted by one. Initializing `cur` and `best` to `1` for nonempty input makes them represent item counts, resetting `cur` to `1` starts a new run at the current item, and updating `best` on every iteration ensures a run reaching the final index is included.

out 316 tok (+135 thinking) latency 5.2 s

Qwen3.8 Max passed · 8/8 cases

```python def longest_run(xs): if not xs: return 0 best = cur = 1 for i in range(1, len(xs)): if xs[i] == xs[i - 1]: cur += 1 else: cur = 1 best = max(best, cur) return best ``` The bug is that the original code starts `best` and `cur` at `0`, so it counts adjacent equal *transitions* rather than the number of items in the run. A run of length `n` has only `n - 1` equal-neighbor transitions, so single-element inputs return `0`, and runs that reach the end are undercounted by one. Initializing the current run to `1` for the first element, resetting it to `1` on a break, and updating `best` from that count fixes the off-by-one.

out 1616 tok (+1411 thinking) latency 34.7 s

Whether the fix is actually correct (runnable), explanation density, and token efficiency on a bounded task.

PROMPT Extract a JSON object with fields {company, quarter, revenue_usd_m, growth_pct, guidance} from this text. Use null for anything not stated; add no other fields. CHECK valid JSON, schema exact

GPT-5.6 Sol passed · 5/5 fields, guidance "withheld pending the Q4 close"

{"company":"Meridian Robotics","quarter":"September quarter","revenue_usd_m":412,"growth_pct":"11+","guidance":"withheld pending the Q4 close"}

out 194 tok (+147 thinking) latency 3.2 s

Qwen3.8 Max passed · 5/5 fields, guidance null

{ "company": "Meridian Robotics", "quarter": "September quarter", "revenue_usd_m": 412, "growth_pct": 11, "guidance": null }

out 1199 tok (+1141 thinking) latency 24.4 s

Schema obedience (no invented fields), hallucination pressure (guidance is explicitly withheld), and structured-output path differences.

PROMPT Write a 120-word product announcement for an API gateway feature that caches prompts across providers. Forbidden words: "seamless", "unlock", "game-changer", "revolutionize", "empower". Exactly one sentence must be a question. CHECK 120 words, 0 banned words

GPT-5.6 Sol passed · 120 words, 0 banned, 1 question

Today, we’re introducing Provider Prompt Cache, a new API gateway feature that reuses prompt prefixes across supported AI providers, reducing latency, token costs, and duplicated processing. Teams can define cache policies once, route requests dynamically, and preserve provider flexibility without rewriting application logic. Switching models during testing or failover? The gateway identifies eligible prompt segments, applies provider-specific caching controls, and reports hits, misses, savings, and expiration details through unified logs and metrics. Configurable TTLs, tenant isolation, encryption, and cache-bypass options help teams balance performance, privacy, and freshness for every workload. Provider Prompt Cache is available today in beta through the dashboard and API, with SDK examples and migration guidance included. […]

out 733 tok (+564 thinking) latency 7.7 s

Qwen3.8 Max passed · 120 words, 0 banned, 1 question

Today, our API gateway adds prompt caching across major model providers. It stores prompts and responses in one fast cache layer. Teams can lower token spend, reduce latency, and repeat reliable answers. The feature supports OpenAI, Anthropic, Google, and Mistral through one configuration. You can set retention rules, scope access, and invalidate entries quickly. How does your team maintain consistent results during provider outages? Approved cached responses keep applications stable while fallback routes recover. The dashboard shows hit rates, savings, latency, and provider usage. Engineers receive audit trails for every cached prompt, enabling safer testing. Product managers can compare cost trends before and after cache adoption. Start with a small route, then safely expand caching to production traffic right now.

out 2744 tok (+2591 thinking) latency 46.3 s

Constraint obedience (word budget, banned-word list, the single question), style fingerprint, and length control.

Switch between them with one line

Both ids are in every tab below — the highlighted pair of lines is the only edit. Same endpoint, same key, same request shape.

from openai import OpenAI

client = OpenAI(
    base_url="https://synthorai.io/v1",
    api_key="sk-syn-...",
)

resp = client.chat.completions.create(
    model="gpt-5.6-sol",
    # model="qwen3.8-max",  # uncomment this line, comment the one above
    messages=[{"role": "user", "content": "Summarize this diff"}],
    reasoning_effort="medium",
)
print(resp.choices[0].message.content)

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FAQ

Which is cheaper, GPT-5.6 Sol or Qwen3.8 Max?

Qwen3.8 Max is cheaper on input / 1m tokens ($2 vs $5, 2.5× apart). Other rows may point the other way — the table above carries the full card, and real cost depends on your mix.

Can I A/B test GPT-5.6 Sol against Qwen3.8 Max without two integrations?

Yes. Both are served through the same OpenAI-compatible endpoint with one API key — switching is a one-line model-string change, so you can route a fraction of traffic to each and compare bills directly.

Do GPT-5.6 Sol and Qwen3.8 Max support prompt caching?

Yes — both bill cached reads below their input rate, so warm-prefix workloads cost less than the list rates suggest. The exact cache-read rows are in the pricing table above.

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