Hello,
That’s strange. Even the old configuration should be more than enough for the plugin. However, the total server memory is not what’s important. What is important is the memory allocated to PHP, and out of that, what portion is actually allocated to WordPress, via the constant WP_MEMORY_LIMIT.
I suspect that the plugin works in your new configuration due to some PHP or WordPress setting, and not due to the machine being more powerful.
with regards