Bun panic crash and degraded performance on Windows ARM64

Description

Claude Code crashes intermittently on Windows ARM64 with a Bun runtime panic. Additionally, overall performance is noticeably slower on ARM64 compared to x64 Intel machines.

Environment

• OS: Windows 11 Home ARM64
• Device: Surface (Snapdragon ARM64)
• Claude Code version: 2.1.49 (win32-arm64)
• Bun version: 1.3.10
• Extension context: VS Code

Crash Details

Bun v1.3.10 Windows arm64. Elapsed: 82693ms. RSS: 0.57GB.

panic(thread 2244): incorrect alignment

Crash Reproduction

• Intermittent during normal usage on Windows ARM64
• Crash about 83 seconds into a session, exit code 3
• Not tied to a specific user action

Performance Degradation

Beyond the crash, everything in Claude Code runs noticeably slower on Windows ARM64 compared to an Intel x64 desktop:

• Tool execution latency: each tool call feels slower
• Hook dispatch: lifecycle hooks add perceptible delay
• Overall responsiveness: the entire interaction loop is sluggish compared to x64

Same workspace, same config, same Claude Code version runs significantly faster on Intel x64.

Impact

• Crash: Session killed mid-conversation, in-progress work lost
• Performance: Degraded developer experience on ARM64 Windows devices

Request

1. Consider upgrading the bundled Bun version if newer releases improve ARM64 stability and performance
2. Evaluate whether bundled native binaries (ripgrep, etc.) are ARM64-native or running under x64 emulation
3. File the alignment crash upstream with Bun if not already tracked

Since Bun is bundled inside the extension, users cannot independently upgrade it.