Hard-Label Distillation: Solving the Memory Blowup

~12 min read

Instead of the teacher's full probability distribution, only its single final output token gets used — dramatically cheaper to store, at the cost of some of soft-label distillation's richer signal. This is what DeepSeek used to distill DeepSeek-R1.

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Key points

  • Hard-label distillation uses only the teacher's final one-hot output token, not its full probability distribution
  • Storage cost drops dramatically — by roughly the vocabulary size — compared to soft-label distillation
  • This is what makes distillation practical at real training-corpus scale, where soft-label storage was infeasible
  • The trade-off: hard labels can't communicate the teacher's confidence or which alternatives it considered plausible
  • DeepSeek used this exact technique to distill DeepSeek-R1's knowledge into Qwen and Llama 3.1 models