I'm wondering about this with memory usage.
I have 4 gigabytes of RAM and I run Ubuntu 64-bit. Yet seemingly, Ubuntu refuses to take advantage of the memory. It recognizes it, but likes to leave about a gigabyte free. Only when I really load up on applications can I push it up to about 3.5 gigs of usage - and then we're talking really loaded. Two virtual machines, Google Earth running, etc.
Currently memory usage according to htop is a smidgen over 3 gigabytes. This is annoying since right now my computer is spending a lot of time moving stuff into and out of swap, which means that the performance is less than stellar. Why is this? Why not use the gigabyte of memory that actually is available instead? To me this makes very little sense.
I know quite a lot about computers, but this has got me stumped is this due to reserved memory and all that hoopla that affects 32-bit systems trying to access four gigs of RAM? I'm planning on adding another four gigs to my system, which of course should alleviate this a bit, but will that then mean that my computer will ignore two gigabytes of memory rather than one?
I'm running Lucid x64 on an AMD Phenom II 955 @ 3.2 Ghz with 4 gigs of ram. It's all patched up with the latest updates. If you need any more information, I will be happy to give it to you. I'm just wondering why my computer ignores a quarter of my memory most of the time, and only uses parts of that ignored quarter when really pushed.
Any help in gaining insight into this is greatly appreciated!
Oh, and I've set swappiness to 0, if that makes any difference.