You often hear how much Linux like memory, and how much it eats up compared to Windows. It’s true! Linux eats into your memory, no matter how much you have, you never seem to have any free for applications to run in! I recently read an article where the author was complaining how Firefox ate into his memory under Vista. The sad fact of it is:
While Linux appears to eat more of your memory, it manages it much better than Windows does.
I have Firefox open right now, I have 10 tabs open with graphics intensive web sites. Firefox is claiming 200Mb of my precious memory… or is it? Actually no: real size in memory 90Mb.
The current list of the most memory intensive applications I’m running, and their “supposed” memory usage:
- Java (Netbeans) 600Mb
- Xorg 380Mb
- Firefox 200Mb
- Thunderbird 130Mb
- Amarok 120Mb
- Kwin (KDE) 120Mb
Now considering I only have 1.5Gb of memory in this machine that 50Mb to much, and considering there are a total of 120 processes running, I haven’t even started to cover the list. Now as any knowledgeable person will tell you, Linux is using some of the hard-drive and pretending that it’s memory, but since a hard-drive is slow, my computer will be running awfully slow.
Wrong! Yes, a disk is much much much slower than memory (especially a laptop drive like this one). However, my computer is running very very fast. Why? Linux’s memory manager notes what parts of memory are used frequently, and what parts are seldom accessed. This means that the parts that are used frequently stay in real memory, and the stuff no-one is using gets stored on the disk.
Translation: Linux will run much faster, and keeps things in memory in such a way as to speed things up! Under Windows, more free memory is better, under Linux it’s the opposite! Less free memory is better, since it means Linux is doing it’s job better.