Default My galaxy s4 has lags?

Hi all, I'm experieng a very bad and fastidious problem. I was on danvdh GE rom with my galaxy gt-i9505 and all was working properly. A day I have the (bad) idea to update the kernel. I was using kt kernel. I updated it and I don't liked because it was a little bit laggy, so i reverted back to a previous version. No way, the lag was still there. I full wiped intalling faux123 kernel but lag was still there. I did many and many full wipes and I tryed many and many roms and kernels. I don't think that my problem is a rom or a kernel. I tryed as well tw roms (unusable with this problems because they are slow and with this problem much more) and GE roms. I also notice a lag in the bootanimation, samsung or ge edition, after a full wipe. What's wrong with my phone? I'm with the old bootloader but I don't think this is the problem because before all was working properly! Do you think that my phone is damaged or what? I tryed as well a Deep Clean 1 but nothing, still laggy! Saying my phone is laggy I mean that:
1) the bootanimation is laggy
2) using the phone I can see animations lags and no smoothness but not ever.. every 1 minute? Don't know what's happening!

Please help me, I'm going crazy! I hate lags... thanks in advantage..

Phone: Samsung Galaxy S IV - GT-I9505
Rom: S4 Google Edition - 4.4.2 - Feel the Experience of Nexus
Kernel:KT-SGS4
Xposed Mods: Gravity Box + Greenify