When comparing Conky vs GKrellM, the Slant community recommends Conky for most people. In the question“What are the best system monitors for UNIX-like systems?” Conky is ranked 3rd while GKrellM is ranked 12th. The most important reason people chose Conky is:
Conky is editable to the point that there is almost no limit to the designs one can use to display the type of information one wants. Not only are there thousands of themes available on sites like deviantart and gnome-look, but a user can create any type of look they like with a little bit of know-how and imagination.
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Pros
Pro Infinitely themeable
Conky is editable to the point that there is almost no limit to the designs one can use to display the type of information one wants. Not only are there thousands of themes available on sites like deviantart and gnome-look, but a user can create any type of look they like with a little bit of know-how and imagination.
Pro Many different sensor stats
Conky has a bunch of sensor stats that the user can choose to display such as CPU usage, memory, uptime, etc. Depending on what the user wants to display, most likely there is a way to display the needed info when using Conky.
Pro Runs on top of X
Pro Customize what to monitor
Users can easily set GKrellM to monitor what they like (depending on what monitors are supported by their PC) such as CPU usage (which can be set to monitor each core individually), as well as temperatures and fan speeds.
Pro Many available plugins
The uses of the monitor can be expanded with available plugins ranging from weather information to TIVO information.
Pro Set up alerts
Through the settings one can set alarms and warning for each monitor, which allows one to always stay informed if anything is getting above what their set limits are.
Cons
Con Setup can be difficult
Being text based, the config file for Conky can be intimidating for those unfamiliar. Though there are configuration managers out there such as Conky Manager which can make the setup a bit easier.
Con Is system monitor but can't manage processes
Conky is a great system monitor, but can't e.g. kill (individual) processes like htop can.
Con Requires X
Cannot easily be used on a headless server or remotely (most people and servers support remoting via SSH).
Con Default theme is not that great looking
The theme that comes by default for GKrellM is not really appealing to the eye and sadly many of the available themes are not that much better with fuzzy text and bad color choices.