Sizing Guide for CrushFTP User Load
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We don't recommend more than 2000 concurrent users for any individual server. A load balancer should be used to help distribute load.

100 concurrent users, S3 storage, 4 cores, 4GB of memory.
500 concurrent users, S3 storage, 8 cores, 16GB of memory.
1000 concurrent users, S3 storage, 16 cores, 32GB of memory.
2000 concurrent users, S3 storage, 32+ cores, 64GB+ of memory.

100 concurrent users, SSD storage, 4 cores, 4GB of memory.
500 concurrent users, SSD storage, 8 cores, 16GB of memory.
1000 concurrent users, SSD storage, 16 cores, 16GB of memory.
2000 concurrent users, SSD storage, 32+ cores, 24GB+ of memory.

Transfer rates are a factor of latency between customer and server, network buffers and TCP window sizes. SFTP suffers the most from latency. CrushClient with its multi segmented TCP transferring can drastically help overcome latency based bottlenecks. Its your fastest option.

16 cores can generally achieve 600Mbit SFTP transfer rates using AES ciphers and Java 17+.
16 cores can generally achieve 1Gbit HTTPS transfer rates using AES ciphers and Java 17+.
24+ cores can generally achieve 2Gbit HTTPS transfer rates using AES ciphers and Java 17+ and very fast disks.

As load increases, more cores will help keep transfer rates higher.
Adding PGP encryption into the mix slows down the file transfer significantly, and it depends on the cipher used. Assume around 300Mbit max speeds with PGP added in.