Xcode Simulator animations extremely slow when played in editor

110
votes

Recently I have experienced, that Xcode's simulator has become extremely slow. Also if I create a new app and run it i, the transition between the launch screen and the first view controller takes about 3 seconds. Luckily it is only the iOS 9 simulator and not iOS 8 or lower. I have upgraded to Xcode 6.4 and I also have Xcode 7.0 beta 3 installed. Has anyone experienced the same? I have tried to uninstall both Xcode versions, but it didn't help.

9
iosxcodeios-simulatorsimulator
Also noticing this. The first launch takes forever, then it will not start the app, have to run it again. After that it's quick. Still very annoying. - User
As for me, the simulator is getting slower and slower. What garbage. - C Johnson
Xcode 9, FPS = 1 all the time. ???? Xcode 8 all works fine (FPS 30) - Mike Keskinov

9 Answers

391
votes

If you press command+T it triggers the 'Slow animations' feature. I didn't noticed this setting until now. Doh!

28
votes

In Simulator menu, go to Debug > Slow Animations , and uncheck this option or simply do:

⌘ + T

5
votes

XCODE 9 BUG. This is officially confirmed to be an issue with Xcode 9.0 and its iOS 11 simulator — it affects any OpenGL-using application.

See: https://github.com/mapbox/mapbox-gl-native/issues/9959

Also: https://twitter.com/xenadu02/status/911463433521860609

:( Hope this helps.

2
votes

Currently only iOS11 simulator is slow.

You can download additional iOS10 simulator which works perfectly.

Choose Xcode -> Product -> Destination -> Download simulators... Then select any iOS10 simulator from the list (e.g. 10.3.1).

enter image description here

After that you will choose iOS version for most devices:

enter image description here

1
votes

This has been fixed in Xcode 9.1 beta 2

Fixed an issue in Simulator’s OpenGL that could cause SceneKit apps to run slowly and the CPU to hit 100% when attempting to pan in an MKMapView.

1
votes

It's known bug by apple developer see below link https://forums.developer.apple.com/thread/83570

0
votes

I had this same problem, and after scratching my head for a while, I realized that having the Xcode "Organizer" window open while running the Simulator causes it to behave very slowly. So for anyone who doesn't have the "slow animations" option ticked, check that the Organizer window isn't open.

0
votes

Xcode simulator has extremely low performance. It is Apple's bug. I have reported it via Feedback Assistant. I have created demo with code demonstrating that simulator is 200 times slower than any old real device. I have found that JavaScript code with Date object executed in WKWebView is pain for simulator. See jsfiddle https://jsfiddle.net/kjms16cw/

var log = document.getElementById("log");
document.getElementById("button").onclick = function() { run(); };

function run() {
	var d1 = new Date();
	for (var i = 0; i < 1000; i++) {
		var x = new Date();
		x.setMilliseconds(0);
		x.setSeconds(0);
		x.setMinutes(0);
	}
	var d2 = new Date();
	log.innerHTML = ((d2.getTime() - d1.getTime()) / 1000) + " seconds";
}
<h3>Xcode Simulator Extremely Low Performance</h3>
<p>This test runs fast (several tens milliseconds e.g. 30 ms)
in any browser any device any platform including very old iOS device
e.g. iPhone 5C and several years old iPad 2, BUT IN SIMULATOR IT TAKES 6000 ms 
(yes, 6 seconds!). Terrible!</p>
<button id="button">run()</button>
<div id="log"></div>
-4
votes

I believe this is an issue with El Capitan, not necessarily Xcode 7 or iOS 9. https://developer.apple.com/library/prerelease/ios/releasenotes/General/RN-iOSSDK-9.0/index.html