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Finch Renderer uses 5.7GB RAM on MacBook Pro (34.8% of 16GB); 15-year-old Windows laptop runs Finch more smoothly #40

Description

@BlessedChild

A cross-platform performance comparison of Finch v1.4.3 on two devices reveals a critical memory management issue on macOS:

Devices tested:

  • MacBook Pro 2017 — i7-7920HQ, 16GB RAM, macOS
  • Lenovo G470 (2011) — i5-2450M, 4GB RAM, Windows 10 Pro 22H2

Key Findings

Metric MacBook Pro 2017 Lenovo G470 (15yr old)
Finch Renderer Memory 5.7 GB (34.8% of 16GB) 1.3 GB (32.2% of 4GB)
Throughput (avg) 0.24ms ✅ 1.56ms
10K lines render 6.6ms ✅ 30.6ms
20 concurrent tasks 4.0ms ✅ 15.6ms
User Experience Score 2.8 / 5 3.8 / 5

Despite having a much faster CPU, the MacBook Pro delivers a worse user experience (2.8 vs 3.8). The root cause is the Finch Renderer process consuming 5.7GB of RAM — nearly 4.5x more than on Windows.

UX Breakdown

Test MacBook Score G470 Score Notes
Quick chat 2-3/5 3/5 Mac has input lag and scroll stutter
Large content 2/5 3/5 Mac freezes during generation
App switching 5/5 5/5 Both fine
Any task execution 1/5 3/5 Mac UI freezes during tasks; G470 stays usable
File operations 4/5 5/5 G470 near-instant
Scroll history 3/5 4/5 G470 smoother

Analysis

The MacBook's Finch Renderer consuming 5.7GB leaves only ~10GB for the OS and other apps, causing swap pressure and UI freezes during any task execution. On the G470, the Renderer uses only 1.3GB, leaving 2.7GB — proportionally similar (~33% of total RAM on both), but the absolute 5.7GB figure is excessive on a machine with only 16GB total.

The irony: a 15-year-old budget laptop runs Finch more smoothly than a 2017 flagship MacBook Pro. This suggests Finch's Electron memory management needs optimization on high-end machines, not just low-end ones.

Suggested Fix Direction

  • Investigate why the macOS Renderer process allocates 4.5x more memory than on Windows for the same workload.
  • Implement memory limits or garbage collection in the Renderer process.
  • Consider whether GPU/WebGL memory allocations on macOS are leaking or over-allocating.
  • Profile memory usage during long sessions — the 5.7GB figure suggests accumulated allocations that are never freed.

Full Report

Full test methodology and results: https://github.com/BlessedChild/finchstory/blob/main/finch-perf-test-comparison.md

Environment

  • Device A: MacBook Pro 2017 · i7-7920HQ · 16GB RAM · macOS
  • Device B: Lenovo G470 (2011) · i5-2450M · 4GB RAM · Windows 10 Pro 22H2
  • App: Finch 1.4.3 (build 1070) — Desktop

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