UltraEdit

UltraEdit is a complete text editor mostly used by professionals in web development and programming, but which can be used by regular individuals as a more complex substitute for Notepad.

It's appreciated by professionals because it offers unique features such as syntax highlighting for nearly every programming language, code folding, and hierarchical function listing and a powerful XML handler.

GUI provides multiple customizations options, such as selection of theme, layout, menu type and other minor settings. The interface has many sections, with lots of features displayed in the menu bar, and a novice user may feel overwhelmed.
Thankfully, the program has a help file where you'll find guidance on any issues you encounter.

Next, to continue the idea from the beginning, UltraEdit supports syntax of various programming languages, such as HTML, PHP, XML, JavaScript, Perl, HEX or Java.
You'll also find a powerful and intuitive-caret editor, so once your cursor is where you want in to be, you can copy, cut, paste and delete just the same as you normally would.

Moreover, it has a search bar that can help you search across files, find expressions or just a simple word.
Additionally, if you need to make quick edits to a file on a server, UltraEdit's integrated FTP capabilities and SSH/Telnet make it easy to work with remote files and interact with servers from a single application.

To summarize, if you want a complex text editor, that uses low memory resources, you can take a shot with UltraEdit.