The file !! _ Functions.ex4 in the original Christmas version from Xard is necessary for the functioning of the ADX & SAR indicator, located in the bottom window. In my setup this indicator does not exist, and accordingly this file is not needed.
The "heaviest" indicator, significantly loading the terminal, in my setup is Markers.
There are also problems with it work when switching trading instruments through the Symbol Changer indicator. But I am not ready to abandon this indicator because it is very functional and allows you to see the situation through several timeframes without switching charts.
I can advise you the following ... Try to tidy up the data files for all trading instruments you use. The number of records for each instrument on any timeframe should preferably not exceed 15000-20000.