I have the aosp browser, but sadly it isn't just internet that is slow. Everything takes a pretty long time to load or open and scrolling stops and stutters. Boot back into my stock ROM and everything is fine again.
If I remember right you installed with Safestrap... I would suggest boot into Safestrap and wipe cache and dalvik. Reboot and see if the gets things smoother. Also debloating your stock side will help. Boot into stock and uninstall all apps that aren't critically important to you, reboot into Safestrap and wipe cache and dalvik (ONLY) on the stock slot . Then boot into ragehd again and see how it runs for you. I did this to my xt912 and it helps immensely!
The limitation of a locked bootloader is the inability to replace stock completely... this eats up room in the phone...housekeeping is important. Hope this helps.