PropertyToIdPerformance.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PropertyToIdPerformance : MonoBehaviour 
{
    public Material mat;
    public bool toggle;
    public int cnt = 5000;
    int propId = 0;
    
    void Awake()
    {
        // プロパティユニークIDの取得
        propId = Shader.PropertyToID("_Test");
    }

    void Update ()
    {
        for (int i = 0; i < cnt; i++)
        {
            if (toggle) {
                mat.SetFloat(propId, 100);
            } else {
                mat.SetFloat("_Test", 100);
            }
        }
    }
}

PropertyToIdPerformance.shader

Shader "Custom/PropertyToIdPerformance"
{
    Properties
    {
        _Test("Test", Float) = 0
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100

        Pass
        {
            CGPROGRAM
            #pragma vertex vert_img
            #pragma fragment frag
            #include "UnityCG.cginc"
            
            fixed4 frag (v2f_img i) : SV_Target
            {
                return fixed4(1,1,1,1);
            }
            ENDCG
        }
    }
}