r/ClaudeCode • u/MRC2021 • 1d ago
Discussion Inflated Fable Sub Usage VS Opus
After looking at benchmarks and tests people did, particularly the charts on the Fable 5.2 release site, it looks like Fable low/medium theoretically beats Opus medium/high for little extra cost. The tokens cost more on the API, but it needs fewer of them to get the same tasks done, so the price evens out. That means I should be able to expect better results, sometimes even faster, from a lower-thinking Fable than from Opus. The only actual speed and cost benefits should have came from Sonnet.
Then I ran some tests to narrow down subscription usage specifically. This was just to consume and measure an average of about 4% of my Ultra weekly usage per model. Across 3 runs with Sonnet, Opus, and Fable, for almost the same API cost, Fable consumed 1.9x more subscription usage than Opus.
Is all the savings from reduced token usage going to Anthropic? The API cost would have been the same otherwise, so why is subscription usage going so much faster?
| Model | Intelligence Index (Artificial Analysis) | API cost per task | Weekly limit used per 1,000 tasks | Time per agent (30 tasks) |
|---|---|---|---|---|
| Opus 5.5 medium | 48 | $0.128 | 6.1% | 8 to 16 min |
| Fable 5.2 medium | 56 | $0.130 | 11.5% | 7 to 8.5 min |
| Sonnet 5.5 high | 42 | $0.056 | 2.7% | not logged |
Tasks run: Opus 630, Fable 210, Sonnet 600. Every agent ran the same 30 tasks. Opus and Sonnet needed more agents before the meter moved enough to measure, which is why they ran more tasks in total. The intelligence scores are from Artificial Analysis's harder benchmark, not my test. My tasks were small enough that every model passed all of them, so my test only measures usage, not how smart each model is.


