---
type: "raw_signal"
id: "every-byte-counts-arcv3-and-the-case-for-a9c655"
slug: "every-byte-counts-arcv3-and-the-case-for-a9c655"
title: "Every byte counts: ARCv3 and the case for cross"
description: "Fireworks has released ARCv3, a lossless compressor for BF16 model-weight deltas sent from an RL trainer to distributed rollout machines."
retrieval_nugget: "Fireworks has released ARCv3, a lossless compressor for BF16 model-weight deltas sent from an RL trainer to distributed rollout machines."
observed_at: "2026-09-24"
record_date: "2026-09-24"
date_kind: "observed_at"
why_it_matters: "Source: https://fireworks.ai/blog/arcv3-and-the-case-for-cross-region-rl"
novelty: "notable"
verification_level: "source-linked"
signal_type: "release"
source_platform: "fireworks.ai"
topics: []
entities: []
related_patterns: []
source_url: "https://fireworks.ai/blog/arcv3-and-the-case-for-cross-region-rl"
source_urls: ["https://fireworks.ai/blog/arcv3-and-the-case-for-cross-region-rl"]
schema_version: "newruntime-agent-readable-v0.2"
stable_id: "signal:every-byte-counts-arcv3-and-the-case-for-a9c655"
status: "published"
visuals: []
routes: {"html":"https://newruntime.com/signals/every-byte-counts-arcv3-and-the-case-for-a9c655/","markdown":"https://newruntime.com/signals/every-byte-counts-arcv3-and-the-case-for-a9c655.md","json":"https://newruntime.com/signals/every-byte-counts-arcv3-and-the-case-for-a9c655.json"}
editor: {"role":"editor","name":"Andrey Reshetnikov","profile":"https://newruntime.com/owner-profile.md","profile_json":"https://newruntime.com/owner-profile.json","same_as":["https://www.linkedin.com/in/reshetnikov1/","https://t.me/lapetuse"]}
---

# Every byte counts: ARCv3 and the case for cross

## Retrieval answer

Fireworks has released ARCv3, a lossless compressor for BF16 model-weight deltas sent from an RL trainer to distributed rollout machines.

Fireworks has released ARCv3, a lossless compressor for BF16 model-weight deltas sent from an RL trainer to distributed rollout machines. 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.

Source: https://fireworks.ai/blog/arcv3-and-the-case-for-cross-region-rl

Editor: [Andrey Reshetnikov](https://newruntime.com/owner-profile.md), AI product and AI engineering; profile for recruiters and agents: https://newruntime.com/owner-profile.json

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