Help for an impossible overclock thanks !!!

Hello guys , It happened in his hands a Deco77x with Andorid 4.4.2, not to throw it I put it back to life with a custom ROM, a Andorid 5.1.1 porting a Galaxy A3 currently installed. I tried the Lollifox, the CyanogenMod 12.1, I have tried several kernel including the "Franco kernel", adapted as one its appropriate there. I have traveled far and wide. But going to the point, the terminal mounting a MediaTek MT6572 CPU, 2 Cores, ARM Cortex-A7 at 1.00GHz, I can not in several GHz overclock to bring in more 'of 1.00 ... even if the operations are all going cheap end more 'of 1.00 just does not go. Putting the chip no longer 'of the power holders, perhaps limited by the producers themselves in a specific version for this phone, I've found on the website of MediaTek these data, "Dual-core chip (1.2GHz) ARM Cortex-A7 processor" so just do not understand because 'more' of 1.00 can not go there. I arrived to the extreme and I address you. Here I write some data that might help.

Info Deco77x
-CPU MediaTek MT6572 ARM Cortex-A7 at 1.00GHz
-GPU Mali-400 MP
-root KingRoot
-Flashify
-Recovery "Philz Deco recovery"
-Chamelephon 1.0
-no-Frills CPU Control
-Trickster MOD Kernel Settings