I have large directories on both sides, which used to load quite fast (few seconds). Since a while both listers are loading quite slow (maybe 2 minutes), since the autosize
is working trough it & it takes quite a time. Is there a way of having the sizes calculated quicker? It seems to have been faster once. I´m not sure if i changed something. 
Are you saying just loading the directories becomes slow?
Or that calculating the sizes of the subdirectories becomes slow?
Or both, or something else?
Those two things are pretty much determined by how fast the OS (and hardware etc.) can return the directory listings.
I have only a few top level folders at both sides, totalling about 200 GBytes (containing the sudirectories), & it seems, that the
calculation speed has slowed down somehow. Since the hardware or fragmentation is about the same as ever, i´m not sure, what could
have caused this. It´s not a big problem anyway, i was only wondering, what could possibly have caused this.
Even if the "size" of the folders hasn't changed alot... are there lots of small files in the folder structure? Folder size calculation takes alot longer with 1 million files worth of data than 1 thousand files of the same size data... Also, has anything changed with your anti-virus software (different version than before, different product all-together)? I don't think most AV software packages should filter meta-data reads to get file-size info, but I suppose some "could"...
There are quite a lot of files, maybe a couple hundred thousands. The antivirus has changed since the new version og Comodo´s CIS. This might be a reason, true.