Claude Sonnet 5 vs Opus 4.8: Cheaper Promo, More Expensive Per Task, Same Censorship
Anthropic positioned Sonnet 5 as "near-Opus power at half the price." It sounds like a no-brainer upgrade for Opus 4.8 users.
We compared both models across benchmarks, real-world per-task cost, and censorship using data from Artificial Analysis, Anthropic's System Card, and our own testing.
The finding that surprised us most: Sonnet 5 costs about 15% more per task than Opus 4.8 at standard pricing (per Artificial Analysis). The cheaper token price is offset by aggressive token consumption at max effort — where Sonnet 5 must run to match Opus performance. And for NSFW creators, the comparison is meaningless — both block adult content completely.
Performance Comparison
We tested both models against independent benchmarks:
Benchmark | Sonnet 5 | Opus 4.8 | Our Take |
|---|---|---|---|
AI Intelligence Index (AA) | 53 | ~55 | Opus 4.8 slightly ahead |
AA-Briefcase (knowledge work) | Near Opus | Excellent | Tie at higher Sonnet cost |
SWE-Bench Verified | +9 pts vs Sonnet 4.6 | Higher | Opus 4.8 |
Terminal-Bench v2.1 | +9 pts vs 4.6 | N/A | Solid improvement |
CritPt (physics reasoning) | 17% (14 pts > 4.6) | Higher | Behind Opus, GLM-5.2, GPT-5.5 |
Cybersecurity (Firefox exploits) | Never completed | Partial success | Opus 4.8 |
The community reaction on Reddit reflects the nuance: "Sonnet 5 is slower, uses more session usage, and delivers worse results than Opus 4.8. It also seems to have more guardrails."
The Real Cost
Raw Token Pricing
Sonnet 5 (Promo) | Sonnet 5 (Standard) | Opus 4.8 | |
|---|---|---|---|
Input | $2/M tokens | $3/M tokens | $15/M tokens |
Output | $10/M tokens | $15/M tokens | $75/M tokens |
Real Per-Task Cost
From Artificial Analysis:
> "Claude Sonnet 5 costs $2.29 per task on the Intelligence Index — ~15% more than Claude Opus 4.8."
Factor | Sonnet 5 | Opus 4.8 |
|---|---|---|
Raw token price | 5-7× cheaper | Expensive |
Max-effort token consumption | 6× more than low effort | Efficient |
Effective per-task cost | ~$2.29 | ~$2.00 |
Promo pricing (to Aug 31) | $2/$10 per M | N/A |
The promo window ends August 31, 2026. After that, Sonnet 5 at standard pricing widens the per-task cost gap.
User Sentiment
YouTube reviewers are split. Some call it "Claude SONNET 5 is Here... & it beats Opus 4.8 for cheaper!" while others title their video "Claude Sonnet 5 IS OUT & ITS HORRIBLE! Worst Model..." The difference depends on use case: Sonnet 5 excels at low-effort simple tasks but its max-effort cost erases the value for complex work.
Where Both Models Block NSFW
This is where the performance debate stops mattering:
Content Type | Sonnet 5 | Opus 4.8 |
|---|---|---|
NSFW image generation | ❌ Refused | ❌ Refused |
Adult content chat | ❌ Refused | ❌ Refused |
Uncensored video | ❌ Not supported | ❌ Not supported |
Explicit roleplay | ❌ Blocked | ❌ Blocked |
Jailbreak resistance | Hardened (reduced sycophancy) | Less hardened |
We found Sonnet 5 is arguably more effective at refusing NSFW than Opus 4.8 — its System Card confirms reduced sycophancy. The model that's theoretically "better" is actually harder to bypass.
The Verdict
For professional work:
Coding/agents: Sonnet 5 at max effort gets close to Opus 4.8 but costs more per task
Cost-sensitive: Stay at low/medium Sonnet 5 effort, accept lower performance
Quality-first: Opus 4.8 still leads and is cheaper per task
For NSFW content: neither works. We built HackAIGC to solve this — uncensored by design, no jailbreaks needed.
FAQ
Is Sonnet 5 better than Opus 4.8?
Sonnet 5 approaches Opus 4.8 at max effort but costs 15% more per task. Opus 4.8 remains ahead on most benchmarks and is cheaper per task.
Is Sonnet 5 actually cheaper?
Per token, yes — 5-7× cheaper. Per task, no — ~$2.29 vs ~$2.00 (AA Intelligence Index).
Do both models censor NSFW?
Yes. Anthropic's constitutional AI blocks adult content on both. Sonnet 5's System Card confirms it's actually more refusal-resistant than Opus 4.8.
What's the best uncensored alternative?
HackAIGC. Our uncensored image generator and uncensored video generator are built without content filters.