Unity how to save and load huge text quickly

I need to save over 500kb of text. Currently it takes 1-2 minutes, what is the best way to read and write text like this.

this is the format that is repeated thousands of times

Name(Position Data)

So what i am doing is looping all gameobjects with tag and then getting there vector3 and the name

when i load i am looping the name(Position Data) and instantiate that block with a variable and setting its name

here is my code for getting the string to write into my file

function GetParams(){
var Out : String = "";
	for (var Go : GameObject in GameObject.FindGameObjectsWithTag("Item")){
		if (Go.GetComponent(ItemController)) {
			//if (CheckIf(Go)) {
				Out += (Go.name + "[" + Go.transform.position.x + "/" + Go.transform.position.y + "/" + Go.transform.position.z + "/" + BoolToInt(Go.GetComponent(ItemController).Foraged) + "/" + Mathf.FloorToInt(Go.transform.eulerAngles.x) + "/" + Mathf.FloorToInt(Go.transform.eulerAngles.y) + "/" + Mathf.FloorToInt(Go.transform.eulerAngles.z) + "],");
				//Destroy(Go);
			//}
		}
	}
return Out;
}

How are you saving and loading it now?

Ideally you do it all at once in one large blob of data rather than line by line.

File.WriteAllText, File.ReadAllText, File.ReadAllLines, File.WriteAllLines are good places to start.