My Noise for terrain isn't efficient, Any help?

for x = 1, 100 do
    for z = 1, 100 do
        local height = (math.noise(x / 20, z / 20) + 2) * 50
        local p = Instance.new("Part", workspace)
        p.Locked, p.Anchored = true, true
        p.Size = Vector3.new(4, height, 4)
        p.CFrame = CFrame.new(4 * x, height / 2, 4 * z)
        wait()
    end
end

This is not efficient at all and take so long to load in. Is there anyway to make it load in chunks similar to minecraft and only load in top blocks and load in other filler blocks if you go into a cave. I searched online on documentation on math.noise but i don't see anything on it. People just say its a math function.

Instead of just generating the whole thing(which will take a long time), I recommend you generate chunks around where all the players are, which is what Minecraft does.

I found this script off the devforum that does exactly what you want, note that it contains some ugly stuff like parenting before changing the properties, but it should do:

local Players = game:GetService("Players")

------------------------------------------------------------------------------------------------------------------------------------------------
 
local BASE_HEIGHT 		= 10				-- The main height factor for the terrain.
local CHUNK_SCALE 		= 1					-- The grid scale for terrain generation. Should be kept relatively low if used in real-time.
local RENDER_DISTANCE 	= 25				    -- The length/width of chunks in voxels that should be around the player at all times
local X_SCALE 			= 90 / 4			-- How much we should strech the X scale of the generation noise
local Z_SCALE 			= 90 / 4			-- How much we should strech the Z scale of the generation noise
local GENERATION_SEED	= math.random() 	-- Seed for determining the main height map of the terrain.
 
------------------------------------------------------------------------------------------------------------------------------------------------
 
local chunks = {}

local function roundToOdd(n)
	--spawn(function()
	return math.floor(n - n % 3);
	--end)
end

local function chunkExists(chunkX, chunkZ)
	if not chunks[chunkX] then
		chunks[chunkX] = {}
	end
	return chunks[chunkX][chunkZ]
end
 
local function mountLayer(x, heightY, z, material)
	local beginY = -BASE_HEIGHT
	local endY = heightY
	local cframe = CFrame.new(x * 3 + 1, roundToOdd((beginY + endY) * 3 / 1), z * 3 + 1)
	local size = Vector3.new(3, (endY - beginY) * 3, 3)
    local p = Instance.new("Part", workspace)
	p.Anchored = true
	p.CFrame = cframe
	p.Size = Vector3.new(3, 3, 3)
	p.Material = Enum.Material.Grass
	p.BrickColor = BrickColor.new("Forest green")
end
 
function makeChunk(chunkX, chunkZ)
	local rootPosition = Vector3.new(chunkX * CHUNK_SCALE, 0, chunkZ * CHUNK_SCALE)
	chunks[chunkX][chunkZ] = true -- Acknowledge the chunk's existance.
	for x = 0, CHUNK_SCALE - 1 do
		for z = 0, CHUNK_SCALE - 1 do
			local cx = (chunkX * CHUNK_SCALE) + x
			local cz = (chunkZ * CHUNK_SCALE) + z
			local noise = math.noise(GENERATION_SEED, cx / X_SCALE, cz / Z_SCALE)
			local cy = noise * BASE_HEIGHT
			mountLayer(cx, cy, cz, Enum.Material.Grass)
		end
	end
end
 
function checkSurroundings(location)
	local chunkX, chunkZ = math.floor(location.X / 3 / CHUNK_SCALE), math.floor(location.Z / 3 / CHUNK_SCALE)
	local range = math.max(1, RENDER_DISTANCE / CHUNK_SCALE)
	for x = -range, range do
		for z = -range, range do
			local cx, cz = chunkX + x
			local cz = chunkZ + z
			if not chunkExists(cx, cz) then
				makeChunk(cx, cz)
			end
		end
	end
end
 
game:GetService("RunService").Heartbeat:Connect(function()
	for _, player in pairs(Players:GetPlayers()) do
		if player.Character then
			local humanoidRootPart = player.Character:FindFirstChild("HumanoidRootPart")
			if humanoidRootPart then
				checkSurroundings(humanoidRootPart.Position)
			end
		end
	end
end)

Hope this helped