Hi Joachim,
Sorry for the late reply. I was on personal leave.
I think you have enabled fetch thumbnail from website using “force” option.
But even when this is enabled, the plugin internally caches the data. It should not slow down.
Can you please check if you have enabled “debugging mode” accidentally?
Go to this page – Settings –> Super RSS Reader – PRO –> Select “Debugging logs”. It is ON, please disable.
Thanks,
Aakash