Hey there! Let's tackle your frame rate questions one by one—this is a super common challenge when targeting a wide range of Android devices, so you're not alone here.

Can I set a universal 120fps for all devices? #

Short answer: No, you really shouldn't. Here's why:

• Low-end devices simply can't sustain 120fps. Trying to force this will lead to constant frame drops, stuttering way worse than your original 30fps issue, plus excessive battery drain and overheating. Players on these devices will have a terrible experience.
• Even some mid-range phones that technically support 90/120Hz might struggle with resource-heavy game scenes (like busy combat or open-world areas), leading to inconsistent frame rates that feel jarring.

Is it better to not set a frame rate at all? #

Leaving Application.targetFrameRate unset lets Unity render as many frames as possible, but this isn't ideal either:

• You'll get unpredictable frame rate spikes and drops when the device's CPU/GPU is under load, which can break gameplay feel (especially for fast-paced games).
• It wastes unnecessary power on devices that don't need extra frames, leading to shorter battery life—something players hate.
• Screen tearing might become more noticeable without VSync enabled to cap frames to the screen's refresh rate.

How to choose the right frame rate for your game? #

The best approach is dynamic adaptation combined with player choice. Here's a step-by-step breakdown:

1. Detect the device's supported refresh rates #

Use Unity's built-in APIs to find out what the device can handle. For Unity 2020.1:

• Check Screen.currentResolution.refreshRate to get the current screen's refresh rate.
• Fetch all supported resolutions with Screen.resolutions, then sort them by refresh rate to find the maximum available.

2. Implement tiered frame rate caps #

Group devices by performance and set appropriate caps:

• High-end devices (e.g., OnePlus 8, Samsung S series): Cap to the device's maximum supported refresh rate (120/90Hz) if your game can sustain it consistently.
• Mid-range devices: Stick to 60fps—this is the sweet spot between smoothness and performance for most phones.
• Low-end devices: Cap to 30fps to ensure stable performance without overtaxing hardware.

You can use hardware specs to tier devices:

• Check SystemInfo.systemMemorySize (in MB) to gauge RAM.
• Use SystemInfo.processorCount or SystemInfo.processorFrequency to assess CPU power.
• Combine this with refresh rate detection to make smarter decisions.

3. Add a player-facing frame rate option #

Give players control over their experience. Add a settings menu with options like:

• Performance Mode: 30fps (battery-friendly)
• Balanced Mode: 60fps
• Smooth Mode: 120/90fps (if supported)

This lets players choose between smoothness and battery life, which is a big win for user satisfaction.

4. Use VSync to sync with screen refresh rate #

Enable VSync via QualitySettings.vSyncCount to prevent screen tearing. Set it to 1 to sync every frame, or 2 to sync every other frame (for lower-end devices if you want to cap at half the screen's refresh rate).

Example Code Snippet #

Here's a quick script to dynamically set a frame rate cap based on device specs:

using UnityEngine;
using System.Linq;

public class FrameRateManager : MonoBehaviour
{
    void Start()
    {
        // Get max supported refresh rate
        int maxRefreshRate = Screen.resolutions.Max(res => res.refreshRate);
        
        // Default target is max, adjust based on hardware
        int targetFrameRate = maxRefreshRate;
        
        // Tier 1: Low-end (under 4GB RAM)
        if (SystemInfo.systemMemorySize < 4096)
        {
            targetFrameRate = 30;
        }
        // Tier 2: Mid-range (4GB to 6GB RAM)
        else if (SystemInfo.systemMemorySize <= 6144)
        {
            targetFrameRate = Mathf.Min(maxRefreshRate, 60);
        }
        // Tier 3: High-end (over 6GB RAM)
        else
        {
            // Let it use max, but ensure it's at least 60
            targetFrameRate = Mathf.Max(maxRefreshRate, 60);
        }
        
        // Set the target frame rate
        Application.targetFrameRate = targetFrameRate;
        
        // Enable VSync to match screen refresh
        QualitySettings.vSyncCount = 1;
    }
}

5. Test on real devices #

Nothing beats testing on actual target devices. Check frame stability in resource-heavy scenes, monitor battery usage, and make sure the experience is consistent across your supported device range.

Final Takeaway #

Don't force a universal 120fps, and don't leave frame rates unregulated. Instead, dynamically adapt to the device's capabilities and give players control. This way, you'll deliver a smooth experience on high-end phones while keeping performance stable on lower-end ones.

内容的提问来源于stack exchange，提问作者emorphus