This article reports IBM Lotus Notes Traveler 8.5.1 performance results for Microsoft Windows 64-bit operating systems. In addition, it compares the performances of Lotus Notes Traveler 8.5 (64-bit) server and IBM Lotus Notes Traveler 8.5.1 (64-bit) server. Lotus Notes Traveler 8.5.1 for IBM Lotus Domino 32-bit servers was not tested because large deployments of Lotus Notes Traveler server are preferred on Lotus Domino 64-bit servers...

Source: http://www.ibm.com/developerworks/lotus/library/notes851-travperf/index.html