Despite more than 250 new features, we aren't aware of any fundamental changes in Apple's new OS X Lion operating system that would affect performance after upgrading. It still offers 64-bit processing, and with Apple's tight control over Mac hardware components, there's no reason to anticipate a learning curve like Microsoft's partners had to deal with when Vista upended the Windows driver model.
Still, the version of iTunes that ships with Lion supports 64-bit processing for the first time. We also wonder about any performance impact from Lion's new auto-versioning feature. There's also the question of how well third-party programs will make the transition in these early days, since they might still be awaiting optimization.
With the 3.1GHz 27-inch iMac on hand from our review this past spring, we took the opportunity to see if Lion introduced any major performance variations compared with our Snow Leopard results on the same system.… Read more