Version: 2018.1
public static int vSyncCount ;

Description

The VSync Count.

The number of VSyncs that should pass between each frame. Use 'Don't Sync' (0) to not wait for VSync. Value must be 0, 1, 2, 3, or 4.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour { void Example() { QualitySettings.vSyncCount = 1; } }

See Also: Quality Settings.