Diff Viewer

Diff Viewer is a Java-based utility that enables you to visually compare text documents by placing them side by side. The highlight color indicates which lines are identical and different. The tool has just a couple of options.

No setup required, besides Java

As long as you have Java installed on your computer, you don't need to set up anything else. This means that you can save the executable JAR file in a custom location on the HDD or copy it to a USB flash drive, in order to launch the program on any workstation. It doesn't need anything else to run, change the Windows registry configuration, or create files on the disk. In order to uninstall it, all you have to do is delete this file.

Simple interface with confusing color codes

When it comes to the interface, Diff Viewer opts for a single window with a minimalistic appearance, showing two vertical panes for typing or pasting two texts. Lines are compared in real time and numbered, so you can easily spot the corresponding ones.
Unfortunately, the color codes are not intuitive. For example, if two lines are identical, their background remains white, while different lines are highlighted in blue. However, it sometimes show red or green highlights after creating a new line.

Evaluation and conclusion

It didn't put a strain on system performance in our tests, using a low amount of CPU and RAM. No error dialogs popped up and it didn't freeze or crash.
Sadly, Diff Viewer features a very light set of options, doesn't make room for customization, and sometimes displays confusing highlights. We must also take into account that it hasn't received updates for a long time. Nevertheless, you can test it for yourself, since it's free for non-commercial use.