Here is a Mod firmware for the Cube U23GTC4-W tablet with these changes :

• V6 supercharging vith all tweaks, zipalign etc... 

        http://forum.xda-developers.com/showthread.php?t=991276

• Low Ram usage, some services and apps removed
• U23GT chinese keyboard removed, replaced by Google Keyboard and converted to system app
• Google play replaced by Google Play Mod by Chelpus.
• Arctools updated
• Explorer replaced by Solid Explorer
• Supersu updated
• Lucky Patcher added
• Play Games added
• Launcher removed and replaced by Apex launcher with S4 theme and converted to system app
• Es Task Manager added and startup items optimized
• Antutu Cpu Master added and configued to 1400~1600mhz with performance governor, and screen off profile as batterysaver 312~504mhz
• Samsung S3 build.prop to better Google Play
• Android original boot animation
• Other settings changed to speed
• Busybox added

How to install :

Flash this Rom : 

http://www.arctablet.com/blog/forum/cube-u23gt/rom-cube-u23gtc4-w-quad-core-android-4-1-1-custom-root-firmware-version-1-06-20130802/

Enter on Arctools install CWM and reboot

put the folder "clockworkmod" on the root of your internal memory, inside CWM go to "backup and restore" and choose restore.

Images :

Download :

http://www.uptobox.com/w4528qp6d4to.html

http://bayfiles.net/file/13gNl/GlDRew/U23GTC4-W_Custom_Firmware_V6_uperCharged_.rar

http://www.mirrorupload.net/host-38/1MAFCRCZ/

http://uploadhero.co/dl/06f0420d

http://bitshare.com/files/cv0tqfgu/U23GTC4-W-Custom-Firmware-V6-uperCharged-.rar.html