… and what a beauty it is, you can read all about it here.
From the Apple site :
New quad-core Intel Core i5 processors are standard on the new iMac. Choose a 21.5-inch iMac with a 2.5GHz or 2.7GHz quad-core Intel Core i5. Or expand your view with a 27-inch iMac featuring a 2.7GHz or 3.1GHz quad-core Intel Core i5.
Full brightness with no waiting. That’s the advantage of the LED-backlit iMac display. Unlike displays that take time to warm up before they reach maximum brightness, an LED-backlit display is instantly on and uniformly bright. LED backlighting also lets you finely tune the iMac display to suit the ambient light in even the dimmest room.
The 21.5-inch iMac features 1920-by-1080 resolution. The 27-inch iMac boasts even greater resolution of 2560-by-1440.
Premium display technology called in-plane switching (IPS). IPS gives you a bright picture with excellent color — even if you’re viewing the display from the side.
With advanced AMD Radeon HD graphics processors across the line, iMac performs even better than before — up to three times better, in fact.1 So you see more frames per second in 3D games, and you can edit HD home videos with more speed and responsiveness.