The iMac is  a line of Macintosh desktop personal computers, released by Apple Inc. The features that can be currently found in the Apple’s iMac configuration are  Intel Core processors, GeForce nVidia graphic or ATI Radeon High definition  integrated cards. Also, the displays can be either 21,5 inch or 27 LCDs.
Although the elder models of iMac had a polycarbonate white case, the older generation have a shaped and styling enclosure. When you see them you can easily think to Apple’s Cinema Displays, a product line of flat widescreen monitors, or to an iPhone. Following the success of the MacBook Pro, the designers used this model of assembly, incorporating in iMac an unibody case. Yet, the elder model of this product, the aluminum one, had a black back, made of plastic.
In a Steve note at the MacWorld conference from January 10, 2006, it was announced that the iMac will be the 1st MacIntosh that will use and Intel Processor, in a Core Duo system. That was the moment when started a 6 month period of transition between PowerPc and Intel. Since the iMac G5, the only thing that changed was the processor’s  speed , the price, the design or the features remaining the same.
The 1st computers from this line, along with the MacBook Pro, represent the first Apple’s computers with an Intel CPU. Since they introduced the iMac Core Duo, and had a real success, the other product lines have adopted this configuration, including the Mini Mac at the start of 2006, the MacBooks at the middle of the same year, followed immediately by Mac Pro, on August, and the Xserve in November.
In February 2006, users reported that the products have some video display problems, like random lines on screen or video bucking. Â These major problems have been solved with an immediate software upgrade.
At the end of 2006, Apple Inc. introduced a version of  iMac that had a Core Duo chip inside and a much lower price. Also, they added a 24 inch model that can support a resolution of 1920 x 1200 pixels that stands for widescreen ultra extended graphics array and have a 16:10 screen aspect ratio. That represented the first iMac that could display HDTV video mode, a system that uses full frames just like a jpg picture, in 1080 TV lines of progressive scan. Also, they released  on this product and a VESA mount, a flat display mounting interface. With the exception of the 17 inch model, all the versions included also and a IEEE 802.11n-2009 draft card.
Making a comparison between the early 2006 models, the Intel Core Duo and the Intel Core 2 Duo models, released in the late 2006, we will review the technical configurations and we will figure that there aren’t too many differences. They have both an white polycarbonate enclosure and can be found in a 17″ 1440 x 900 and 20″ 1680 x 1050 matte display form, all wide screen. Yet, the second model can be found also in a 24″ 1920 x 1200 variant, also matte.
On the graphic card side we can see a major difference. The first model had an ATI Radeon X1600 graphic, with 128 MB SDRAM, or, as an option, with 256 MB available for the 20″ model. The late model have either an Intel GMA 950 with 64 MB memory shared with the main one, either an ATI Radeon X1600, either a nVidia GeForce 7300 GT with 128 MB of GDDR3. The last model it is available and with 256 MB of GDDR3 SDRAM, only for the 24 inch models.
Both use a serial ATA hard drive with 160 GB or 250 GB capacity and 7200 rotations per minute. Optional, the user can acquire a  500 gigabytes one.
The earlier model had an 1,83 GHz Intel Core Duo processor with 2 MB on-chip L2 cache, unlike the younger model  that is an 1,83 GHz T5600 Core 2 Duo for the low-end 17″ only, or a 2.0 GHz T7200 for the high- end 17″. Optional, you can choose a 2,16 GHz processor or a 2,33 GHz for the 20 inch and 24 inch models.
The Air Port it is integrated in the both models and they are disabled by default. The later model have and a 24x combo drive, available as an optional for the low- end 17″ only. Both, the first and the second model have as internal slot- loading an 8x Super Drive with 2.4x double layer recording for DVDs, rewritable DVDs and rewritable CDs.
Steve Jobs introduced in July, 2009, a fully restyle of iMac, providing an aluminum and matte glass design. The only screw that it is visible on this models it is right in front of memory slots and it is made to assure an easy access to them. The back it is now solid and black and it is not anymore removable. They totally removed the 17 inch model and introduced a 24 inch one.
In March, 2009, Apple Inc introduced a brush up to iMac product line with a USB port, a double RAM capacity, a slimmer restyled base and leaving only one FireWire Port.