First of all why would you need to defrag the registry ? Or the ram for that matter. I have never done either. Just my hard drive. Computer runs fine. I see a lot of computers come threw my shop. That have had windows messed up over these so called cleaners. If you just do a regular clean up with a temp cleaner and Defrag. The computer will run fine. This is just my opinion.
Everyone input is a value here. We all should take note of that! I been at this for a very long time. But everyone going to do things a bit differently.
RAM as you know Windows is suppose to release RAM when the Application is ended. That's not always the case. Thus the need for what we call Virtual RAM (aka Swap File) Where Windows developers decided back in the Windows 3.x days to use part of the HDD as RAM. Thus Write/Reads were slow back then.
So day that part of the HDD is still be use to store data in a buffer as RAM but really it's storing it on HDD. Thus that area get fragmented.
Registry when you install and remove software the registry keeps a index record of the application once you install it or decide to remove it. So the registry has space in there. So the idea is to Defrag Registry. All it's doing is remove that extra space and compacting the Registry file. Thus the idea here is since all the space is compressed the system will run faster.
Also not really a good idea to run a lot of cleaners on the system. You should really choose 1 or 2 of them you trust. For me I've tried pretty much them all. I've narrowed my favorites too.
1. JetClean Pro (Free version is available to download from Techspot)
2. UnCleaner V1.7 (Free small program) Use google to search for it.
3. Ultra Defrag (Outsource (FREE)
That's about it you don't want to run too many cleaners. Just keep it simple. On yes best to start when you first get your PC too. Keep up the cleaning just think of it like owning your Vehicle. You keep the up-keep on it. So the same with the Windows. Android has no HDD but sort of SSD (RAM/ROM) mix so you would still need to flush out the junk files too.
Again, everyone input is a value here! We all should take note of that! But everyone going to do things a bit differently. But in the end you find the common solution to your most effective cleaning method.