You can transfer files on one site while browsing another a site or browse a folder on a site while transferring files from the same site.
Multiple Concurrent Sessions are depicted as multiple open windows in the Remote Pane (on the right side by default). You can tile, cascade, or minimize these windows. When the panes are maximized, select alternate sessions by clicking the tabs at their lower left border.
Click the Site Manager tab.
On the menu bar, click File > Connection > Connect.
Repeat step 2 to connect to more sites. You can connect to the same or different sites.
Go to Tools > Global Options > Transfer.
Clear the Use same session to transfer files less than N kbytes check box, or set N to a very low value.
Go to Tools > Global Options.
Click Connection.
Enter a value between 1 and 200 in Global Max number of connections.
Go to Tools > Global Options.
Click Connection.
Enter a value between 1 and 200 in Max number of connections per site.
Limit the number of concurrent per site transfers allowed
Turn off individual transfer item logging in settings or turn off all logging options in Tools > Global Options > General > Logs.
Turn off the Use same session to transfer files less than N kbytes option in Tools > Global Options > Transfer.
Don't transfer files in Multi-Part mode
Don't perform on-the-fly File Integrity Checking
Close the main program interface and let the Transfer Engine perform the transfer.
On a Windows 95/98/ME computer you can only choose up to 40 concurrent connections.
On a Windows NT/2k/XP computer you can choose up to 200 concurrent connections, but more than 40 connections may compromise system performance.
Connections include transfers, browser sessions, and every single thread in a Multi-Part transfer.
FTP sites that don't support multiple connections or sites that frequently drop the FTP connection will limit concurrent sessions.
Machine resources and slow hardware may limit or prohibit multiple connections as well.