Hi jiskiw
We would suggest you try to reduce the number of products shown per page, as this can affect performance.
As more products per page ATUM has to load, more time will be needed to process them all. This is pretty normal...
Also, as ATUM loads all the variations, if you have many variable products, this increases the real number of products shown on every page.
I hope this helps.
Best Regards,
Salva.