The company reports an average payload equal to 0.19% of original BF16 weight size across 1,000 production RL update deltas, versus 0.36% for ARCv2, 0.35% for PULSESync, and 0.67% for a draft Hugging Face TRL implementation. ARCv3 is the default in the Fireworks Trainer SDK and is also offered through the fireworks-delta-compression package for bring-your-own trainers.
Raw SignalSep 24, 20261 min read1 source
Every byte counts: ARCv3 and the case for cross
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Fireworks has released ARCv3, a lossless compressor for BF16 model-weight deltas sent from an RL trainer to distributed rollout machines.