Apple is expected to reveal faster, more powerful versions of both its 13-inch and 15-inch professional notebooks on Tuesday.

Though neither computer's outward appearance is expected to be altered, what's under the hood is set to get a very impressive upgrade, especially in the case of the 15-inch MacBook Pro, which is expected to get 16GB of RAM as standard, even on the base configuration model.

According to numerous sources, including Apple Insider, each 15-inch notebook is also getting a faster Intel Core i7 processor and better harddrive options too. However, prices are not expected to increase as a result of the component overhaul.

Also, if information that originally is believed to have come from an Apple store in China is totally accurate, Apple might also be planning to introduce a third ‘maxed out' version of the 15-inch notebook as a standalone model which will boast a 2.8Ghz Intel Core i7 processor, 16GB of RAM, a 1TB SSD and Intel Iris Pro and Nvidia GeForce GT 750M graphics.

As for its 13-inch counterpart, French site MacG claims that it is also due for an update on Tuesday but the specifications are not yet clear.

Apple has already released refreshed MacBook Airs and iMacs this year and in updating the internal components has also cut retail prices. The company is widely expected to launch a new notebook later this year that blends the best elements of its MacBook Air range with those of its more potent Pro notebooks.

It is expected to have a 12-inch Retina display and a fan-less design so that it runs very quietly. It is also said to feature a new type of button-less touchpad.

However, a completely new computer isn't expected to launch until the latest version of OSX, Yosemite, is ready for public release, possibly in October this year.