My iPad mini 3 64GB is slower than iPad mini 2 32GB

Both with fresh iOS 9.1 installed. The iOS + game performance seems so much better and fluid on the mini 2 than on my mini 3 when they should perform the same.

I'm experiencing frame drop in games also whereas the mini 2 is smooth as butter. I tried restoring, tried even the 9.2 beta 4 with same results. Is it hardware problem? Please help.

Also just so you know it has like 50GB free space so space isn't the issue.