If you query the ADSM-L archives for "multi-session" and "collocation," you'll see the latter is definitely discussed more than the former — way more. Which is actually better for improving TSM restore speeds? This blog entry attempts to discuss the pros and cons of both, as well as what you need to do to activate either one.
----- Signature and Disclaimer -----
Written by W. Curtis Preston (@wcpreston). For those of you unfamiliar with my work, I've specialized in backup & recovery since 1993. I've written the O'Reilly books on backup and have worked with a number of native and commercial tools. I am now Chief Technical Architect at Druva, the leading provider of cloud-based data protection and data management tools for endpoints, infrastructure, and cloud applications. These posts reflect my own opinion and are not necessarily the opinion of my employer.