look at the back of the iphone, whats the model number stated?

probably sound like a locked unit.

9.3.1 looks ok for me. I disabled the spotlight search, maybe that helps.

disable the spotlight search for the affected apps? You are using 6/6 plus?

Disable all!!! i did this when 9.1 or 9.2 came out. 6 plus was sooooo sluggish...

6 plus. (I got a 6s also).

Will try it later and see
My last gen 6 plus is sluggish especially in loading / starting apps as others before me have pointed out

My 6s+ npo. Super smooth

Forgot, I did two things when things slow down for me using iphone 6+

1) Settings -> General -> Spotlight search (turn off everything even Siri suggestions)

2) Settings -> General -> Background app refresh off
What I believe is, save battery usage since apps doesn't work background and memory/CPU usage while another app gets open.
Downside is you lose "background app refresh" capability.

Let me know if it helps for you. It did for me. I nearly wanted to upgrade to 6s + when 6+ got sluggish.

Just did the 2 suggestions you mentioned. And rebooted the phone just in case.
Starting the FB app (for the 1st time) still takes a good 7 secs.
How about you?

Model number is A1586 

A1586 should me msian set and should be able to activate...

unless its US set... sprint or something. 

Uhm... sorry if you had an impression it helps speed things up. It doesn't.

It helps in minimizing slowness & sluggishness.

My iPhone 6 battery percentage seemed to have some issue, it turn off by itself before reaching 0%, sometime at 30+% turn off already. Plugging into charger turn on with 19% most of the time, then in 1 min become 26% and then charge normally up to 100%.

I tried restoring the phone to default iOS without beta but doesn't seemed to have helped. However I did a battery capacity check with some software and found that the battery capacity is now at 1700 from 1751 original capacity. (Which I think is extremely healthy, but calibration issue, problem begin after one of the beta update for 9.3)

Is there any solution to fix this? Or do I have to replace the battery with a new one?

My iPhone warranty has expired on February, roughly how much if  I were to replace it in original Apple service center in Mid Valley? I quoted from outside shop for around 150~250.

Is it wise to replace ip6+ with ipSE?

Is it wise to replace ip6+ with ipSE?

sorry guys.. need some help from you all..

may i know that if i don't back up my iphone and updating my iphone thru phone itself  is that possible my photo and contact are gone?

No. Should still be there unless something goes wrong during updating - which is rare.