Apple wanted to send us the $1,949 27in iMac, but could only get us the smaller 21.5in model in time for our roundup. In terms of raw hardware, the only difference between the two is the LCD panel: the 27in model has a resolution of 2,560 x 1,440 pixels, while the 21.5in panel is 1,920 x 1,080. Otherwise, both have a Radeon HD 6770M graphics chip, 4GB of RAM and a 1TB hard drive. Up against the Dell and Lenovo all-in-ones, the iMac does pretty well on both performance and storage, although there’s only a standard DVD burner rather than Blu-ray. As for which CPU it uses, Apple claims it’s a 2.7GHz Intel Core i5, but it doesn’t match up with any on Intel’s site. Apple Australia wouldn't clarify the exact processor model when asked, but our guess is it’s either a custom chip or a downclocked Core i5-2300.







May I suggest that it could be the i5-2500S?
http://ark.intel.com/products/52211/
Matches up with Apple's claims as far as I can tell...
It might be - you'd have to get Apple to confirm that.
Lots of luck...
Cheers, Darren.