Verdict
Built from the measurements below
- Accuracy is too close to call: Ling 3.1 Flash scored 41.2% and Phi 4 41.2% on the same 80 questions, a gap within what chance alone could produce.
- Phi 4 is 5.1× cheaper per question as billed ($0.00012 vs $0.00061), reasoning tokens included.
- Phi 4 generates text 14× faster: 103 tokens per second against 7.
- Phi 4 starts answering sooner: 0.5 s to the first token, against 1.1 s for Ling 3.1 Flash.
- Ling 3.1 Flash accepts more context: 262k tokens against 16k.
Which should you choose?
Choose Ling 3.1 Flash for a 262k-token context window. Choose Phi 4 for the lower cost per correct answer ($0.00029 against $0.0015), faster streaming, a quicker first token, shorter outputs (about 699 tokens per question against 2,616) and open weights you can run yourself. The widest subject gap is in engineering: Phi 4 answered 6 of 15 correctly, Ling 3.1 Flash 1 of 15. With so few questions per subject, treat this as a lead to test on your own prompts, not a result.
Accuracy gap +0.0 points (z = 0.00). We call a winner only when z is at least 1.96, the usual 95% threshold. Speed, latency and price need a 10% margin.