Apple has unveiled new all-in-one iMac systems, sporting an updated processor, more standard memory and a faster graphics card.

Retail customers will be offered new systems with Intel Core2 Duo chips ranging from 2.4GHz to 2.8GHz.

Apple will also offer a new 3GHz Intel chip as an option for built-to-order 24in iMac systems. All the new iMacs will feature a faster 1066MHz system bus and 6MB of level 2 cache.

All but the cheapest of Apple's three standard iMac offerings will now ship with 2GB of Ram.

The $1,199 20in model will sport 1GB of Ram and an ATI Radeon 2400 XT graphics card. The $1,499 model will have a Radeon 2600 Pro card, as will the $1,799 24in iMac.

Apple will also offer the Nvidia GeForce 8800 GS card as an option on built-to-order 24in systems.

The new offerings mark the first major update to the iMac since August 2007, when a redesign offered a slimmer profile and a brushed aluminium casing.

Apple's latest financial report showed flourishing Mac sales, helping to boost the firm to record profits in the most recent quarter.

Philip Schiller, senior vice president of worldwide product marketing at Apple, said: "With the latest Intel processors, a faster new graphics option and more memory, customers now have even more reasons to love the iMac."