Speculation over what Apple will announce at the special press event being held on 12 September is heating up, after the company makes an announcement this week about a major upgrade to its iMac and Mac Minis.

Every iMac and Mac Mini will now be equipped by Intel Core 2 Duo processors, and the iMac range now has a 24-inch widescreen display version as its top-of-the-line model.

The basic 17-inch iMac has dropped in price to $999, while the Mac Minis have received their Intel upgrade without any added cost.

There are now four iMac models: a 1.83GHz and a 2.0GHz 17-inch; a 2.16GHz 20-inch, and the new 2.16GHz 24-inch.

Specifications on the new 24-inch include standard Core 2 Duo processor with 4MB of shared L2 chache, 1GB of 667MHz DDR2 RAM, a 250GB hard drive, Nvidia GeForce 7300 GT graphics with 128MB of memory, and a SuperDrive for burning DVDs and CDs.

It can further be ramped up to a 2.33GHz processor, up to 3GB of ram, a 500GB hard drive, and an Nvidia graphics card with 256MB of memory.

All the iMacs come with iSight webcams, as well as a built-in AirPort Extreme, five USB ports, two FireWire ports, and Ethernet connectivity.

The 24-inch iMac costs $1999; the 20-inch, $1,499; and the 17-inch 2.0GHz version, $1199.