PrimateLabs, the developers of GeekBench have published benchmark comparisons for the new Core 2 Duo Mac Mini and new aluminum iMacs.
Apple's Mac Mini update replaced the aging Mac Mini's Core Duo processor with a Core 2 Duo. Their conclusion was that moving from Core 2 Duo and clock speed updates provide "modest" performance improvements but "no real reason to upgrade" from the previous generation Mac Mini. Speed increasines were much more dramatic, however, for owners of the PowerPC or Core Solo Mac Mini. (graphs available)
Apple's iMac update brought in the Santa Rosa chipset (faster front-side bus) along with the option for the faster (2.8GHz) Core 2 Duo Extreme processor. Both of these improvements can bring increase in performance, especially in memory intensive applications such as Aperture and Photoshop. (graphs available)
Update: Barefeats posts some gaming/graphics benchmarks that show less than desirable results for the new iMac's Radeon 2600 HD vs. the previous iteration's GeForce 7600 option. The site has promised to re-run the tests under Windows XP to see if the issue is driver-related, as Windows drivers would be more mature than Mac OS X versions (note: driver issues were to blame for initially low-scoring current MacBook Pro benchmarks).
