Lumia 920 issues

[Zen8]

So I've this phone since December 2012 and well,it's amazing.I've recently updated to Black while gdr3 with the preview in September I guess.Anyway I'm experiencing some issues so let's start.
1. After Black update I've noticed that battery lasts less,it actually discharge abou 3%/12 min without using the phone,having just WI fi on and battery saver no glance double tap to awake nor high sensitivity,I have also low brightness.Before it used to last longer or maybe it's just me.I've unplugged phone from charger 3 hours ago and it is at 70%.
2. Continuing about battery issue,I noticed that locking and unlocking the phone the battery drastically goes Down,in 1 minute of lock-unlock it drained almost 20%!Is there a problem with my phone or someone else is experiencing this?
3.With GDR3 preview I'm actually seeing the first lags and some apps crash like settings and IE,yeah and it's depressing,well they are rare but sometimes they happen.
4. I've checked my memory and it says that settings occupies 4,1GB!How is it possible?It's getting more frustrating than Other storage that it's REgiving me problems,now it's locked at 5 GB and I've deletes temporary files.I'm thinking of hard resetting the phone.
About this,I have bad experience since last time it bricked my phone on the gears for 7hours 'till I found a key combination so I'm really afraid that I couldn't be that lucky,even if I have warranty extension for 3 years I don't and can't stay without my phone for long time.So my question is,in case of bricking is there ant solutions apart going in a Nokia centre or where I bought the phone?Cause I know I have to wait "a bit".
5. There are some other issues that I have,but I can't figure them out right now,in case that I'll remember I'm going to update this post!
Thank you guy,see ya!

 

[InvisGhost]

Those problems all come with using a preview build. That's why it's rolled out as a preview and not a stable build. Don't think of it as a "get access to a polished product before all your friends!" thing, think of it as a "try out this thing and tell us how it fails because we know it will". My suggestion would be to hard reset your phone and wait for the stable update to be released for it. You can use the hardware button combination to reset the phone if it gets stuck on the spinning gears screen. The following page will also provide you with some support: Your Windows Phone 8 doesn't work or respond as expected

 

[Zen8]

Actually I haven't done it For "hey yo bro a got da update 3 fo first!!1!!!".Not really for that.
I had read it was actual the final version of the gdr3 so well I just tried but anyway as I said crashes etc. Are pretty rare so not a true problem at all.
Anyway,yesterday night I have soft resetted my phone and let it charge all the night,and I can see some improvements,4h standby + 1h of WI FI turned on it was 99%.
Later on 20 minutes of games and it went down to 94% right now it's at 92% but I have everything turned off apart WI FI.
I think I'll hard reset now and then downgrade to gdr2,later on I'll update to GDR3 when it comes.
Anyway thank you for the answer!

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