Has your Notification Center ever lagged while opening? For me it takes around 3-5 seconds to open. I found a working solution and if your affected by this problem, try the following.
1- Open Settings on your device.
•Either drag them down:
4- Test your Notification Center. If it still lags, remove a few more apps.
*Tweaks could also be removed.
That’s it! As simple as counting to 10. Your Notification Center should no longer lag. If it still does even after following all these steps, it could be a Notification Center related tweak.
Let me know if this solved your problems!