djp, the reason why the -rt switch uses more memory and speeds up the folding client is because it reduces the need to read from disk.

Without the -rt switch, the client needs to read the protein.trj file each time it works on a protein and this takes time since reading from the hard drive or a USB memory stick or CD or whatever is much slower than RAM.

Using the -rt switch loads the protein.trj file into memory so it no longer needs to read this data from disk each time it works on a protein.

That is why the readme says up to 150 MB of RAM because the size of the proteins the DF project is expecting to work on won't exceed that limit with the protein.trj file.

Hope that helps explain why using more memory wouldn't speed things up the way the client is currently designed.

Jeff.