[Koha] KOHA technical upgrade question

[erlanda_simonyan at flib.sci.am]

Dear List,
In the Fundamental Scientific Library, we use Koha version 25.05.03.000, on the Xeon® Processors E3-1240 v6, RAM 32GB, HDD 1+1TB. Also, active circulation is functioning.
Our catalog consists of 536,000 records with ca. 900,000 items. 
Our Koha is operating slowly, and we think that the technical parameters of our server are not enough for satisfactory performance. 
Can anybody recommend what server to use?
Thanks,
Erlanda