Hacker News Reader

Comment by sydney6 | Hacker News Reader

Unused memory is wasted memory, they say.

Yeah, software takes more ram, so when your ram is full your computer is slowed (because it probably doesn't need only 100% if your ram), therefore you buy more ram. Now guess what? your ram is not at 100% anymore, your unused memory is wasted anyway, so why not use it?

Repeat the cycle.

Not exactly -- more like no matter how much RAM you have, it makes sense for your software to use it all rather than disk.

It means that however much you have, your system should use as much of it as possible. Otherwise it's just sitting there doing nothing. Contrary to popular belief, the more RAM you're using, the faster your system will be (assuming it's using the RAM efficiently)

>Contrary to popular belief, the more RAM you're using, the faster your system will be (assuming it's using the RAM efficiently)

Is this a joke? If I have 16GB of RAM but my programs use 18GB then my system will suddenly become faster?

Free memory is always used by disk cache.

On Linux, not all of it, in my experience. If you have a lot of memory, some of it may be completely free.

Only a very small percentage is kept "free". Everything else should be made available to buffer cache or the application, etc....

It should gradually trend towards using the vast majority of the free space. The disk cache won't consume memory unless you're reading new, not-already-cached pages from disk; so if you're not reading enough data from disk, then it might not consume everything. (E.g., if you've rebooted recently, and just haven't read enough from disk to consume everything.)

If you work w/ removable media, IME the cache will free the pages associated w/ that media when it's removed (as the cache must be assumed invalid when/if the media is plugged back in). Playing a DVD, and then ejecting it, would often result in a large drop in disk cache. (Back before Netflix…)

Reply on news.ycombinator.com