What is the maximum fasta file size allowed for creating a udb with USEARCH 32-bit?

Or how can we calculate it?

So far we have tried a 1.3GB fasta file, but it's too large and we run out of memory (though we have 1008GB of RAM)....I think the developer purposefully limits the processing? We are thinking about buying the commercial version, but in the meantime it would be nice to know the maximum fasta file size we could use to create a database.

Thanks!