The first table said 0.632. The real score was 0.845
Bugs first. I ran three closed models on my 50 tasks. The harness printed a table, and one model sat at 0.632, well below the others.
That wasn't the model's score. On 13 of the 50 tasks the provider returned an empty response and the harness recorded a zero. I re-ran only those 13 with the same judges and got 0.845. The table was lying about the model; the fault was in the road to it.
After the fix (one model appears at two settings):
| Score | Time per task | Cost per run | |
|---|---|---|---|
| Model A | 0.852 | 15.5 s | $1.53 |
| Model B | 0.845 | 17.4 s | $0.30 |
| Model C, high effort | 0.833 | 14.2 s | $0.78 |
| Model C, medium effort | 0.809 | 11.8 s | $0.63 |
The measurement's own noise is 0.043: that's how far an identical config moves between re-runs. The first three rows fit inside 0.02. On quality, it's a tie.
Three things I didn't expect:
→ Model C writes three times faster than the others but also produces 2.6 times more text. Per task it takes almost the same time: 14.2 s against 15.5 and 17.4. The speed I see in daily work is a different picture, many short messages in a row, and this test doesn't measure that → Model A costs five times B and adds no quality → Dropping C's effort cost 0.024 points and removed a fifth of the text and 17% of the time
One honest caveat: at the setting I actually use every day, C scored 0.809 and A and B came in about 0.04 higher. That's at the edge of the noise, and one run proves nothing. I need three repeats; they're planned.
I'm not naming the models: the API terms forbid brand-named comparisons. The numbers are real, and the rows are added to the table at bench.csylabs.com.
I'm not changing anything.