Would you like AutoFreeRam (IOS 8) on your iDevice? This tweak is pretty useful for your iPhone performance :
1. add http://cydia.myrepospace.com/mundosapple/ to your Cydia Sources
2. Install AutoFreeRam
3. You can find its configuration in setting > AutoFreeRam
4. Everytime you close every running app in your AppSwitcher, an amount of RAM will be released to gain more RAM to your iDevices.