From WeTekForums:
We was doing some tests of Live TV in combination with tvheadend on OpenELEC at WeTek Play, and there is big improvement of stability and zapping speed when Show signal quality option is turned off.
It seems that pvr addon is sending a lot of requests to tvheadend and causing some performance issues.
To turn off this option, go to:
SYSTEM -> Live TV, here change Settings Level to Expert, then go to Playback inside of Live TV settings, and turn off Show signal quality (see photo).