Hello,
i am new to Xcode and new to Swift 
Since the new update I have really bad Performance on the Simulator no matter which device i choose. I tried to learn Swift with the Book 2D Apple Games and I am on the way to Chapter 3 of the book. I have no errors or warnings and my simulator runs at 2 FPS. Yesterday on Xcode 8 with the same Code I had around 40 FPS with my Macbook 12" '16. Do you have the same Problems?
Thank you very much,
Nils
@henkyboy89. Thanks very much for your question. I personally don’t do any development using beta software, so I unfortunately don’t have any first hand experience with this. I did a quick search on this topic, and found that it is a known issue, and hopefully Apple is working on it. Here is the link directly from Apple’s forums:
https://forums.developer.apple.com/thread/80270
I apologize for not being able to provide a more substantive answer.
I hope this helps!
All the best!
Thank you for your fast answer. Because the simulator was very slow, I found out how to test my App on my physical device and it works very smooth on 60 FPS. That’s maybe the proof that it has nothing to do with my Code or with Swiftupgrade 3->4 but rather the new slow simulator =) Maybe Apple will fix this issue fast.
Greetings,
Nils
Yeah, it’s just a bug in the latest version of Xcode 
Hopefully it’ll be fixed in Xcode 9.0.1
@henkyboy89 I have some very good news for you! I actually found a solution that another developer posted for the same problem that you posted about:
Thanks once again for posting this question, and bringing the issue to our attention
All the best!
Xcode 9 in Simulator is beyond, way beyond unusable. I have timing in apps that are supposed to execute in 0.06 seconds and it take more than 1 second to execute. MapKit is absolute useless and its annotations never display.
I strongly recommend against installing Xcode 9 until Apple solves these fatal flaws.