Sorry for my English.
I noticed this feature.
The duration of the import process becomes longer, the next time you import.
The first import files downloaded literally 20-30 seconds.
Now import occurs 5-7 minutes (weight not file \ number of lines become longer). With each new import load time increases.

Each file contains 5000 entries.
But in the "Processing" hanging figure for all of the downloaded items.
Here is the screenshot exactly what's going on? CS-cart imports of goods ~ 123k?
Is there some kind of cache is responsible for the import function?
Maybe a bug?
The import function will compare items in the file with the already existing entries? For example checks on the article, for the introduction of new price performance.
Then everything is logical.
How to speed up the process?
Tell me please.