Apple Watch Series 3 now crazy slow

Hi Ey_Uup,

Thank you for participating in the Apple Support Communities. We understand your watch has slow performance issues. Have you tried unpairing your watch and setting it up again? This can sometimes resolve issues like this. This article has the steps if needed: Unpair and erase your Apple Watch.

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How to unpair and erase your Apple Watch if you have your iPhone

1. Keep your Apple Watch and iPhone close together as you unpair them.
2. Open the Apple Watch app on your iPhone.
3. Go to the My Watch tab and tap All Watches.
4. Tap the info button  next to the watch that you want to unpair. 
5. Tap Unpair Apple Watch.
6. Tap Unpair [your Apple Watch name].
7. For GPS + Cellular models, choose whether to keep or remove your cellular plan. 

• If you want to pair your Apple Watch and iPhone again, keep your plan. 
• If you don't want to pair your Apple Watch and iPhone again, remove your plan. If you aren't going to pair with a different watch or iPhone, you might need to contact your carrier to cancel your cellular subscription. 

8. Type your Apple ID password to disable Activation Lock, then tap Unpair. 

Before erasing all content and settings on your Apple Watch, your iPhone creates a new backup of your Apple Watch. You can use the backup to restore a new Apple Watch. After your Apple Watch unpairs, you'll see the Start Pairing message.

Now you can set up your Apple Watch again or turn it off if you're selling it or giving it away.

How to erase your Apple Watch if you don't have your iPhone

1. On your Apple Watch, tap Settings > General > Reset > Erase All Content and Settings. 
2. Type your password if prompted.
3. For GPS + Cellular models, choose to keep or remove your cellular plan.

• If you want to pair your Apple Watch and iPhone again, keep your plan. 
• If you don't want to pair your Apple Watch and iPhone again, remove your plan. If you aren't going to pair with a different watch or iPhone, you might need to contact your carrier to cancel your cellular subscription. 

4. Tap Erase All to confirm. This resets your Apple Watch to the factory settings.

Now you can set up your Apple Watch again. You'll need the Apple ID and password associated with the watch turn off Activation Lock.

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You'll also want to make sure your watch is not low on storage space as this can affect performance.

You may also want to check the Maximum Capacity of the battery. On the watch go to Settings > Battery > Battery Health. If that is close too or below 80% it may be affecting performance.

Take care.