Once you have gathered information about your computer's hardware, check that your hardware will let you do the type of installation that you want to do.
Depending on your needs, you might manage with less than some of the recommended hardware listed in the table below. However, most users risk being frustrated if they ignore these suggestions.
A Pentium 4, 1GHz system is the minimum recommended for a desktop system.
Tabell 3.2. Recommended Minimum System Requirements
The minimum values assumes that swap will be enabled and a non-live image is used. The «No desktop» value assumes that the text-based installer (not the graphical one) is used.
The actual minimum memory requirements are a lot less than the numbers listed in this table. With swap enabled, it is possible to install Debian with as little as 350MB. The same goes for the disk space requirements, especially if you pick and choose which applications to install; see Del D.2, «Disk Space Needed for Tasks» for additional information on disk space requirements.
The installer normally automatically enables memory-saving tricks to be able to run on such low-memory system, but on architectures that are less tested it may miss doing so. It can however be enabled manually by appending the
lowmem=1 or even
lowmem=2 boot parameter (see also Del 184.108.40.206, «Check available memory / low memory mode» and Del 5.3.2, «Debian Installer Parameters»).
Installation on systems with less memory or disk space available may be possible but is only advised for experienced users.
It is possible to run a graphical desktop environment on older or low-end systems, but in that case it is recommended to install a window manager that is less resource-hungry than those of the GNOME or KDE Plasma desktop environments; alternatives include
wmaker, but there are others to choose from.
It is practically impossible to give general memory or disk space requirements for server installations as those very much depend on what the server is to be used for.
Remember that these sizes don't include all the other materials which are usually to be found, such as user files, mail, and data. It is always best to be generous when considering the space for your own files and data.
Disk space required for the smooth operation of the Debian GNU/Linux system itself is taken into account in these recommended system requirements. Notably, the
/var partition contains a lot of state information specific to Debian in addition to its regular contents, like logfiles. The dpkg files (with information on all installed packages) can easily consume 40MB. Also, apt puts downloaded packages here before they are installed. You should usually allocate at least 200MB for
/var, and a lot more if you install a graphical desktop environment.
 Installation images that support the graphical installer require more memory than images that support only the text-based installer and should not be used on systems with less than 780MB of memory. If there is a choice between booting the text-based and the graphical installer, the former should be selected on such systems.