ideal_ms

Metric: ideal ms (The Heartbeat)

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Executive Summary

ideal ms represents the hardware target. It is the exact amount of time between two monitor refreshes (the VSync interval). This is the "metronome" that the entire rendering engine must follow.

• 60Hz: 16.67 ms
• 120Hz: 8.33 ms
• 144Hz: 6.94 ms
• 240Hz: 4.17 ms

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Why this number matters

ideal ms defines your total "time budget." If your GPU work plus your CPU work exceeds this number, you will miss a refresh, causing the vblank mul to jump and the sync score to tank.

1. The Goalpost: Every other metric (slack ms, drift ms, sync) uses this value as its reference point.
2. Detection: Your tool calculates this by querying the Linux DRM subsystem. If this number is wrong (e.g., your 144Hz monitor is showing 16.67ms), your OS or cable is capping your performance.

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How it impacts your OSD

Because ideal_ms is a constant based on your hardware, it acts as the denominator for your efficiency:

• Slack vs Ideal: If your ideal ms is 8.33 and your slack ms is 4.0, you are using roughly 50% of your available time.
• Drift vs Ideal: If your drift ms is half of your ideal ms, you are landing exactly in the "dead zone" between refreshes.

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Troubleshooting

If ideal_ms is...	It means...	The Fix
Higher than expected	Your monitor is running at a lower refresh rate.	Check display settings or use a DisplayPort cable.
Fluctuating	You likely have Adaptive Sync (VRR/G-Sync) enabled.	Do nothing. This is normal for VRR as the heartbeat matches the GPU.
Perfectly steady	You are in a fixed-refresh mode.	Ensure your "Budget" is always under this number.

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