Yes, you can preview effects using timeline preview rendering since version 16.08 (video tutorial):
- Set in and out points using I and O keys for the area in which your effect is active.
- In the main menu in Timeline/Timeline Preview press Add preview zone.
- In the same menu, press Start Preview Render and wait until the red bar turns green at the top of the timeline.
Any change to the area - including moving clips or adding effects to clips in it - will result in requiring to re-render to regain the playback speed enhancement.
In case 16.08 or later is not available on Linux Mint yet, you might be able to install it manually (video guide):
sudo add-apt-repository ppa:kdenlive/kdenlive-stable
sudo apt-get update
sudo apt-get install kdenlive