How to swap internal and external memory Android 5.1?

Does anybody know how to swap internal and external memory on S3 Neo? I am using Resurrection Remix Rom

Performance questions - swap, RAM; Google Play Music

Hello!
I've been using XT1032 for a while as someone that's mostly new to smartphones - it's an upgrade after heavily worn out LG GT540. However after rooting it, installing official CM and updating to the latest nightlies every second day or so, I still have several problems. I'm sorry if there's too little detail in this post, I'll try to add detail later on.
First off, I don't understand how the storage space works. The phone is supposed to have 8GBs of internal memory, however only 5.5GBs are accessible to the user. Additionally, applications refuse to install when the system reports that there's ~400MBs of "space" left. Is this because of a partition being filled up? The Apps panel of system settings isn't specific what is taking up too much space and I'm afraid the DiskUsage app doesn't help either.
Second thing is the actual available RAM. It's supposed to be 1 GB, but Z-DeviceTest reports only 885MBs being available. Where's the rest? There's also swap of 255MBs that I don't know where it came from. I thought that on a low-end smartphone they wouldn't waste internal storage on swap.
There's a trick to increasing available storage space by linking the /cache folder to root. How does that work? How do I know if the folder is being used or not, and if it's safe to do this? DiskUsage doesn't show this folder normally, and when switching to it in root it's being 651MBs large, with "System data" taking up 11.2MBs and pds-CM10.img 3MBs. There's also recovery and backup folders, 56KBs and 16KBs respectively. Why is it this big anyhow, if it's not being used?
The most immediate problem, and the one that annoys me the most since I bought the phone for a certain purpose, is that Google Play Music is lagging terribly. It uses ~110MBs when I switch to the Running Apps screen from the settings quickly enough to check its stats, each song takes several seconds to load even on WiFi, no matter the quality, and the worst part is that even if it "loads up" it takes several additional seconds to scroll around it! It's not just the playing affected, the whole interface is sluggish. Screens take seconds to switch between each other, returning to the app after opening two applications makes it either "restart", where it still plays music, but you can see that the interface is now several screens back. How is it possible that in 2015 an operating system developer can't make a performant app that's not a game, that's not a video editor, but a god damn music player? The only quirk is that it's streaming the music from the net instead of playing a downloaded file. It has a cache that uses over 700MBs already, no excuses. I checked that with DiskUsage.

Edit vold.fstp to swap internal to external sdcard

I am using HTC desire 516 dual sim phone and unable to do anything with 145MB space left in internal memory.
I have rooted my phone as it was already out of warranty and have RootExplorer to access vold.fstb file.
However unable to do so as my file says only
(dev_mount sdcard /storage/sdcard1 auto /devices/msm_sdcc.2/mmc_host) and I am unable to identify the change.

Please help.

Ritesh

SD Card/SIM Hot Swap

Well it's all in the title. I remember seeing somewhere that the phone is fine with hot swaps and hot plugs. However Android still gives a warning when doing so (because of the SIM). I have tried hot swapping a couple times and never had any issue with it. Is it just an alert we can ignore? Or do you think we should always turn off the phone to do so?

Swap motherboards?

I have a D850 with a cracked screen, if I bought a different make of the LG G3 would my motherboard fit in it?
Also is the "ESN" on my motherboard? Could I buy a phone with a bad ESN and put in my motherboard (with a clean ESN) and be good to go?

Thanks in advance

Is it possible to have 2+ Partitions on extSDcard and mount Swap, Link2sd and MultiSy

Hello there.
I am currently running Android 5.0 LP (AllianceROM v9.1.1) on my rooted SGs5 klte G900F using TWRP and 64GB Samsung EVO MicroSDCard.
I just recently ran into some issues and wiped everything and reinstalled Alliance and started anew. B4 this happened i had partitioned my extSDcard and had Link2SD app and mounted my 2nd partition as ext4 and everythijg was fine. I researched about RAM swap so and Multi System Virtual Rom so ibwent ahead and wiped my extSDcard and Repartioned it With a 3rd n 4th partition.
1st partition: 44GB FAT32 for pics, Music ect.
2nd partition: 6GB SWAP for RAM
3rd partition: 6GB EXT4 for Link2SD
4th Partition: 9GB FAT32 for Multi System

I Just mounted my 2nd partition for SWAP and is working.
However i just opwned LINK2SD PRO and did as i did before and attemoted to mount scripts to ext4 and reboot and now i get an error saying Unable to mount: Invalid Arguement...

IF ANYONE CAN plz help me oit with this id greatly appreciate it as i have no clue what to do from here. Thank you for your time.