Apple announced on Tuesday that it has updated its high-end MacBook Pro laptops with faster processors, better graphics and more memory space.

The laptops are still available in three models: two 15.4-inch versions that retail for AU$2,899 and AU$3,599, and a larger, 17-inch edition that costs AU$3,999. But with Tuesday's update, the lower-end 15-inch model is now equipped with 2.2GHz Intel Core 2 Duo processors (previously, it had a 2.16GHz chip); the higher-end 15-incher and the 17-incher now come with 2.4GHz processors, up from 2.33GHz. These new processors are indeed Intel's latest Centrino -- or "Santa Rosa" -- chips, which were introduced in early May.

All three MacBook Pros additionally now can be upgraded from 2GB to 4GB of RAM (random access memory) at extra cost, and have faster Nvidia GeForce 8600M GT graphics cards designed for media-intensive animation and gaming.

The 15-inch models also have an energy-efficiency boost, with LED-backlit displays. Apple has touted these not only as power-saving but also mercury-free.

The announcement comes on the heels of another Apple laptop upgrade: In May, the company released new versions of its lower-priced MacBook machines. Those laptops received processor and memory upgrades in addition to a hard-drive space boost (which was not part of Tuesday's MacBook Pro boost), but did not come with Santa Rosa processors or LED-backlit screens, as had been rumoured.

The last major update to the MacBook Pro laptops was in October, when they were first manufactured with Intel Core 2 Duo processors.

It's shaping up to be a hot summer for Apple. The company is expected to make more product announcements -- though no one's really sure what they will be -- at its Worldwide Developers Conference next week. Additionally, perhaps its most hotly anticipated product ever, the iPhone, will hit US stores on June 29. The iPhone is expected to launch in Australia next year.