While the main use for an SD card is to expand your device’s storage, it is possible to use a portion of it as additional RAM to improve Android’s system performance.
Available from the Play store for £6.99/$9.99, Roehsoft RAM Expander (SWAP) works on rooted phones and has a checker app, called MemoryInfo & Swapfile Check, that should be installed first to confirm that the main app will be able to run on your Android phone.
Tap Start Ramexpander Test Here in the checking app, select your SD card and then Click for result. If the results are favourable then you can install the main app.
Once running, select the Optimal Value for the swap (this can be adjusted later), remembering to ensure that Autorun is enabled. Finish by tapping Swap Active.