Hi Geoff,
Super RSS Reader has a very light foot print.
It does not keep a lot of stuff in the memory. There is no specific number I can provide as it is insignificant.
The error you see is something even before RSS feed data is fetched.
Can you please let me know what is the size of the RSS feed you are trying to fetch ?
Can you share the URL here ?
If that is small then it is defintely a server issue, where PHP is running short of memory.
The Curl error 28 is something related to the server where the CURL module is unable to fetch the result on time. This can be for any URL which is being tried not related to Super RSS Reader or WordPress itself.
You can read more about it here – https://kb.mailpoet.com/article/311-curl-issue-28-timeout
Thanks,
Aakash