diff --git a/assets/cubyz/shaders/graphics/graph.vs b/assets/cubyz/shaders/graphics/graph.vs
index 847228790..1a9d27cb3 100644
--- a/assets/cubyz/shaders/graphics/graph.vs
+++ b/assets/cubyz/shaders/graphics/graph.vs
@@ -7,7 +7,7 @@ uniform vec2 screen;
 uniform int points;
 uniform int offset;
 
-layout(std430, binding = 4) buffer _data
+layout(std430, binding = 5) buffer _data
 {
 	float data[];
 };
diff --git a/src/graphics.zig b/src/graphics.zig
index 9ddd00c1f..ce60628ee 100644
--- a/src/graphics.zig
+++ b/src/graphics.zig
@@ -380,6 +380,12 @@ pub const draw = struct {
 	pub fn text(_text: []const u8, x: f32, y: f32, fontSize: f32, alignment: TextBuffer.Alignment) !void {
 		try TextRendering.renderText(_text, x, y, fontSize, .{.color = @truncate(u24, @bitCast(u32, color))}, alignment);
 	}
+
+	pub fn print(comptime format: []const u8, args: anytype, x: f32, y: f32, fontSize: f32, alignment: TextBuffer.Alignment) !void {
+		const string = try std.fmt.allocPrint(main.threadAllocator, format, args);
+		defer main.threadAllocator.free(string);
+		try text(string, x, y ,fontSize, alignment);
+	}
 };
 
 pub const TextBuffer = struct {
diff --git a/src/gui/gui.zig b/src/gui/gui.zig
index 21026d7f8..9f84d9763 100644
--- a/src/gui/gui.zig
+++ b/src/gui/gui.zig
@@ -241,6 +241,26 @@ pub fn openWindow(id: []const u8) Allocator.Error!void {
 	std.log.warn("Could not find window with id {s}.", .{id});
 }
 
+pub fn toggleWindow(id: []const u8) Allocator.Error!void {
+	defer updateWindowPositions();
+	for(windowList.items) |window| {
+		if(std.mem.eql(u8, window.id, id)) {
+			for(openWindows.items, 0..) |_openWindow, i| {
+				if(_openWindow == window) {
+					_ = openWindows.swapRemove(i);
+					selectedWindow = null;
+					return;
+				}
+			}
+			try openWindows.append(window);
+			try window.onOpenFn();
+			selectedWindow = null;
+			return;
+		}
+	}
+	std.log.warn("Could not find window with id {s}.", .{id});
+}
+
 pub fn openHud() Allocator.Error!void {
 	for(windowList.items) |window| {
 		if(window.isHud) {
diff --git a/src/gui/windows/_windowlist.zig b/src/gui/windows/_windowlist.zig
index 2ef39a705..3d45cd0e4 100644
--- a/src/gui/windows/_windowlist.zig
+++ b/src/gui/windows/_windowlist.zig
@@ -4,6 +4,7 @@ pub const chat = @import("chat.zig");
 pub const controls = @import("controls.zig");
 pub const creative = @import("creative.zig");
 pub const crosshair = @import("crosshair.zig");
+pub const debug = @import("debug.zig");
 pub const graphics = @import("graphics.zig");
 pub const healthbar = @import("healthbar.zig");
 pub const hotbar = @import("hotbar.zig");
@@ -11,6 +12,7 @@ pub const inventory = @import("inventory.zig");
 pub const inventory_crafting = @import("inventory_crafting.zig");
 pub const main = @import("main.zig");
 pub const multiplayer = @import("multiplayer.zig");
+pub const performance_graph = @import("performance_graph.zig");
 pub const settings = @import("settings.zig");
 pub const sound = @import("sound.zig");
 pub const workbench = @import("workbench.zig");
\ No newline at end of file
diff --git a/src/gui/windows/debug.zig b/src/gui/windows/debug.zig
new file mode 100644
index 000000000..1093a6437
--- /dev/null
+++ b/src/gui/windows/debug.zig
@@ -0,0 +1,51 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+
+const main = @import("root");
+const graphics = main.graphics;
+const draw = graphics.draw;
+const Texture = graphics.Texture;
+const Vec2f = main.vec.Vec2f;
+
+const gui = @import("../gui.zig");
+const GuiWindow = gui.GuiWindow;
+const GuiComponent = gui.GuiComponent;
+
+pub var window = GuiWindow {
+	.contentSize = Vec2f{128, 16},
+	.title = "Debug",
+	.id = "cubyz:debug",
+	.isHud = false,
+	.showTitleBar = false,
+	.hasBackground = false,
+};
+
+fn flawedRender() !void {
+	draw.setColor(0xffffffff);
+	var y: f32 = 0;
+	try draw.print("    fps: {d:.0} Hz{s}", .{1.0/main.lastFrameTime.load(.Monotonic), if(main.settings.vsync) @as([]const u8, " (vsync)") else ""}, 0, y, 8, .left);
+	y += 8;
+	try draw.print("    frameTime: {d:.1} ms", .{main.lastFrameTime.load(.Monotonic)*1000.0}, 0, y, 8, .left);
+	y += 8;
+	try draw.print("window size: {}×{}", .{main.Window.width, main.Window.height}, 0, y, 8, .left);
+	y += 8;
+	if (main.game.world != null) {
+		try draw.print("Pos: {d:.1}", .{main.game.Player.getPosBlocking()}, 0, y, 8, .left);
+		y += 8;
+		try draw.print("Game Time: {}", .{main.game.world.?.gameTime.load(.Monotonic)}, 0, y, 8, .left);
+		y += 8;
+		try draw.print("Queue size: {}", .{main.threadPool.loadList.size}, 0, y, 8, .left);
+		y += 8;
+		// TODO: biome
+		y += 8;
+		// TODO: packet loss
+		y += 8;
+		// TODO: Protocl statistics(maybe?)
+	}
+}
+
+pub fn render() Allocator.Error!void {
+	flawedRender() catch |err| {
+		std.log.err("Encountered error while drawing debug window: {s}", .{@errorName(err)});
+	};
+}
\ No newline at end of file
diff --git a/src/gui/windows/performance_graph.zig b/src/gui/windows/performance_graph.zig
new file mode 100644
index 000000000..cb982931e
--- /dev/null
+++ b/src/gui/windows/performance_graph.zig
@@ -0,0 +1,84 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+
+const main = @import("root");
+const graphics = main.graphics;
+const draw = graphics.draw;
+const Texture = graphics.Texture;
+const Vec2f = main.vec.Vec2f;
+
+const gui = @import("../gui.zig");
+const GuiWindow = gui.GuiWindow;
+const GuiComponent = gui.GuiComponent;
+
+pub var window = GuiWindow {
+	.contentSize = Vec2f{128, 64},
+	.title = "Performance Graph",
+	.id = "cubyz:performance_graph",
+	.isHud = false,
+	.showTitleBar = false,
+	.hasBackground = false,
+};
+
+var lastFrameTime: [2048]f32 = undefined;
+var index: u31 = 0;
+var ssbo: graphics.SSBO = undefined;
+var shader: graphics.Shader = undefined;
+const border: f32 = 8;
+
+var uniforms: struct {
+	start: c_int,
+	dimension: c_int,
+	screen: c_int,
+	points: c_int,
+	offset: c_int,
+	lineColor: c_int,
+} = undefined;
+
+pub fn init() !void {
+	ssbo = graphics.SSBO.init();
+	shader = try graphics.Shader.initAndGetUniforms("assets/cubyz/shaders/graphics/graph.vs", "assets/cubyz/shaders/graphics/graph.fs", &uniforms);
+}
+
+pub fn deinit() void {
+	ssbo.deinit();
+}
+
+fn flawedRender() !void {
+	lastFrameTime[index] = @floatCast(f32, main.lastFrameTime.load(.Monotonic)*1000.0);
+	index = (index + 1)%@intCast(u31, lastFrameTime.len);
+	draw.setColor(0xffffffff);
+	try draw.text("32 ms", 0, 16, 8, .left);
+	try draw.text("16 ms", 0, 32, 8, .left);
+	try draw.text("00 ms", 0, 48, 8, .left);
+	draw.setColor(0x80ffffff);
+	draw.line(.{border, 24}, .{window.contentSize[0] - border, 24});
+	draw.line(.{border, 40}, .{window.contentSize[0] - border, 40});
+	draw.line(.{border, 56}, .{window.contentSize[0] - border, 56});
+	draw.setColor(0xffffffff);
+	shader.bind();
+	graphics.c.glUniform1i(uniforms.points, lastFrameTime.len);
+	graphics.c.glUniform1i(uniforms.offset, index);
+	graphics.c.glUniform3f(uniforms.lineColor, 1, 1, 1);
+	var pos = Vec2f{border, border};
+	var dim = window.contentSize - @splat(2, 2*border);
+	pos *= @splat(2, draw.setScale(1));
+	pos += draw.setTranslation(.{0, 0});
+	dim *= @splat(2, draw.setScale(1));
+	pos = @floor(pos);
+	dim = @ceil(dim);
+	pos[1] += dim[1];
+
+	graphics.c.glUniform2f(uniforms.screen, @intToFloat(f32, main.Window.width), @intToFloat(f32, main.Window.height));
+	graphics.c.glUniform2f(uniforms.start, pos[0], pos[1]);
+	graphics.c.glUniform2f(uniforms.dimension, dim[0], draw.setScale(1));
+	ssbo.bufferData(f32, &lastFrameTime);
+	ssbo.bind(5);
+	graphics.c.glDrawArrays(graphics.c.GL_LINE_STRIP, 0, lastFrameTime.len);
+}
+
+pub fn render() Allocator.Error!void {
+	flawedRender() catch |err| {
+		std.log.err("Encountered error while drawing debug window: {s}", .{@errorName(err)});
+	};
+}
\ No newline at end of file
diff --git a/src/main.zig b/src/main.zig
index fe7dfb5da..b928fda06 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -188,6 +188,16 @@ fn takeBackgroundImageFn() void {
 		std.log.err("Got error while recording the background image: {s}", .{@errorName(err)});
 	};
 }
+fn toggleDebugOverlay() void {
+	gui.toggleWindow("cubyz:debug") catch |err| {
+		std.log.err("Got error while opening the debug overlay: {s}", .{@errorName(err)});
+	};
+}
+fn togglePerformanceOverlay() void {
+	gui.toggleWindow("cubyz:performance_graph") catch |err| {
+		std.log.err("Got error while opening the performance_graph overlay: {s}", .{@errorName(err)});
+	};
+}
 pub var keyboard: struct {
 	// Gameplay:
 	forward: Key = Key{.key = c.GLFW_KEY_W},
@@ -221,6 +231,10 @@ pub var keyboard: struct {
 	textPaste: Key = Key{.key = c.GLFW_KEY_V, .repeatAction = &gui.textCallbacks.paste},
 	textCut: Key = Key{.key = c.GLFW_KEY_X, .repeatAction = &gui.textCallbacks.cut},
 	textNewline: Key = Key{.key = c.GLFW_KEY_ENTER, .repeatAction = &gui.textCallbacks.newline},
+
+	// debug:
+	debugOverlay: Key = Key{.key = c.GLFW_KEY_F3, .releaseAction = &toggleDebugOverlay},
+	performanceOverlay: Key = Key{.key = c.GLFW_KEY_F4, .releaseAction = &togglePerformanceOverlay},
 } = .{};
 
 pub const Window = struct {
@@ -464,6 +478,8 @@ pub const Window = struct {
 	}
 };
 
+pub var lastFrameTime = std.atomic.Atomic(f64).init(0);
+
 pub fn main() !void {
 	seed = @bitCast(u64, std.time.milliTimestamp());
 	var gpa = std.heap.GeneralPurposeAllocator(.{.thread_safe=false}){};
@@ -539,7 +555,7 @@ pub fn main() !void {
 	c.glEnable(c.GL_BLEND);
 	c.glBlendFunc(c.GL_SRC_ALPHA, c.GL_ONE_MINUS_SRC_ALPHA);
 	Window.GLFWCallbacks.framebufferSize(undefined, Window.width, Window.height);
-	var lastTime = std.time.milliTimestamp();
+	var lastTime = std.time.nanoTimestamp();
 
 	while(c.glfwWindowShouldClose(Window.window) == 0) {
 		{ // Check opengl errors:
@@ -552,8 +568,9 @@ pub fn main() !void {
 		Window.handleEvents();
 		c.glClearColor(0.5, 1, 1, 1);
 		c.glClear(c.GL_DEPTH_BUFFER_BIT | c.GL_STENCIL_BUFFER_BIT | c.GL_COLOR_BUFFER_BIT);
-		var newTime = std.time.milliTimestamp();
-		var deltaTime = @intToFloat(f64, newTime -% lastTime)/1000.0;
+		var newTime = std.time.nanoTimestamp();
+		var deltaTime = @intToFloat(f64, newTime -% lastTime)/1e9;
+		lastFrameTime.store(deltaTime, .Monotonic);
 		lastTime = newTime;
 		if(game.world != null) { // Update the game
 			try game.update(deltaTime);