What's using up my RAM on Sony Xperia U?

[SwiftGale]

My RAM nowadays is constantly above 90%. I?m using an Xperia U, which has 512mb of RAM (339MB is available). Back when I first bought the phone, I was able to play games with no problems at all (maybe just an occasional lag). But since the time I upgraded to ICS, it seems like my phone?s performance is deteriorating. I never really used to check my phone?s used RAM before, but I don?t remember it being that high.
Anyway, I added up all the running services (foreground, background, cached, everything) and it only amounted to 184.6MB. And yet it says that 334MB is used. Does this mean that there are some hidden services running? I heard that the system reserves part of the RAM for itself, that?s why I only get 339MB out of 512MB (feel free to correct me if I?m wrong). But then that should still give me 149.4MB of free RAM. So my question is, what?s using the remaining RAM, and is there anything I can do to clear it up?
I ask this because some games and apps just keep on freezing or crashing when I use them. Its getting really bad that Im considering buying a new phone, though I'd rather just continue using my current one.
Thanks for reading this wall of text. Any advice is much apprieciated!

 

[Aquila]

Android (Linux) uses RAM differently than PC's do, more about that can be found here: http://forums.androidcentral.com/samsung-galaxy-tab-pro-10-1/373222-ram-usage.html - but the short version is that it's not bad for it to be using RAM and you don't have to micromanage RAM.

One thing that may help with performance is booting into recovery and clearing the cache, however this is a two year old budget device on ICS, so it doesn't benefit from a lot of the optimization for low end devices that came about in Kit Kat or even the TRIM support from 4.3. This is one of those things where clearing the cache and/or a factory reset may help, but it also could just be the age showing.

 

[lokomotifbag]

Android (Linux) uses RAM differently than PC's do, more about that can be found here: - but the short version is that it's not bad for it to be using RAM and you don't have to micromanage RAM.

One thing that may help with performance is booting into recovery and clearing the cache, however this is a two year old budget device on ICS, so it doesn't benefit from a lot of the optimization for low end devices that came about in Kit Kat or even the TRIM support from 4.3. This is one of those things where clearing the cache and/or a factory reset may help, but it also could just be the age showing.

Thank you for the explanation... good luck