This week Apple released its updated line of iMac computers which feature Sandy Bridge quad-core processors from Intel and new AMD Radeon graphics processors.

Apple says the new iMac's, which start at $1,199 in Canada and the United States, are up to 70 percent faster and new graphics deliver up to three times the performance of the previous generation.

First introduced in MacBook Pro computers in February, the new iMacs also feature Thunderbolt I/O technology. The 21.5-inch iMac has a single Thunderbolt port while the 27-inch model features two ports.

With two bi-directional channels, Apple claims that Thunderbolt, a technology developed by Intel, can transfer files at 10 gigabits per second, about twelve times faster than FireWire and twenty times faster than USB 2.0.

Thunderbolt aslo offers native support for Mini DisplayPort and through the use of adapters connect to DisplayPort, DVI, HDMI, and VGA displays. Up to seven devices can be daisy-chained off a single Thunderbolt port.

Physically, the iMac continues to feature its signature aluminum and glass design, IPS LED-backlit high resolution display, SD card slot and comes with Apple’s Magic Mouse or Magic Trackpad.

The iMac comes with Mac OS X Snow Leopard and iLife, Apple’s suite of applications for creating and sharing photos, movies and music.

Also included in the new generation of iMacs is a built-in FaceTime HD camera and Apple’s FaceTime software. The new camera supports high definition video calls between all FaceTime HD-enabled Macs and standard resolution calls with iPad 2, iPhone 4, the current generation iPod touch and other Intel-based Macs.

Pricing & Availability

The 21.5-inch iMac is available in two configurations: one with a 2.5 GHz quad-core Intel Core i5, AMD Radeon HD 6750M and 500GB hard drive for $1,199 and one with a 2.7 GHz quad-core Intel Core i5, AMD Radeon HD 6770M and 1TB hard drive for $1,499.

The new 27-inch iMac is available in two models: one with a 2.7 GHz quad-core Intel Core i5, AMD Radeon HD 6770M and 1TB hard drive for $1,699 and one with a 3.1 GHz quad-core Intel Core i5, AMD Radeon HD 6970M and 1TB hard drive for $1,999.

Configure-to-order options include faster Intel Core i7 processors up to 3.4 GHz, additional hard drive capacity up to 2TB, a 256GB solid state drive, and additional DDR3 memory.

Discuss the new iMac's in Digital Home's Apple Computing forum .