Let's create some folders with thousands of items in them (I tested up to 40,000 files) and time how fast xplorer² is in a variety of view modes. First let's try details mode, which is the fastest.
We see that in detailed view mode (which arguably most of you use), reading speed is quite snappy, and increases almost linearly with the number of files (40K files read in 1.14 sec). The delay in reading is almost imperceptible.
Plain list view mode is also as fast as details, but you need to turn on the maximum column width constraint from program options, which increases the reading speed dramatically.
Moving on to thumbnails, things go downhill, and reading speed suffers. It is 10 times slower to read folders in thumbnails mode, and that's without taking thumbnail extraction into account! Even worse, the trend is slightly exponential, compared to the linear increase in detailed mode:
Even windows explorer is faster than this. Technically speaking, the problem is windows listview control in autoarrange mode, which takes ages to calculate the positioning of items. Of course you don't care about that... I must apologize for the inconvenience caused and promise to look into it for a forthcoming xplorer² upgrade.
The only consolation is that folders containining under 10000 files are not really affected.