Apple’s new 15in MacBook Pro line-up may look identical to its predecessor (the mid-2009 models that brought the fixed battery and SD card slot to the line), but under the hood, changes to both the CPU and GPU combine to make an impressive leap in performance over the systems these replace.

The new 15in MacBook Pro comes in three standard configurations. All three models come standard with 4GB of DDR3 RAM, two graphics processors, and a glossy 15.4in LED-backlit screen.

The £1,499 entry-level system comes with a 2.4GHz Core i5 processor and a 320GB hard drive. The next step up the line is a £1,649 system with a 2.53GHz Core i5 processor and a 500GB hard drive. At the top of the line sits a £1,799 model with a 2.66GHz Core i7 processor and a 500GB drive.

What’s new?

The new 15in MacBook Pro models drop the Intel Core 2 Duo processors (used in Apple’s laptop line since late 2006) in favour of Intel’s Core i5 and Core i7 mobile processors. The Core i5 and i7 processors have a few interesting performance features, including Hyper-Threading, which uses virtual cores to double the amount of processing cores presented to the operating system. The processors have dual cores, but OS X treats them as having four cores. Another i5/i7 technology, Turbo Boost, allows the processor to speed up for a short period of time when necessary, or shut down unused cores and give the resources to the cores in use. Turbo Boost can increase the clock speed of the 2.4GHz Core i5 processor up to 2.93GHz, for example.

The mobile versions of the Core i5 and i7 used in the MacBook Pro differ from the desktop version found in the 27in iMac, which has four physical processing cores. The desktop Core i5 does not support Hyper Threading.

All 15in MacBook Pros now offer both integrated and discrete graphics – previously, the entry level 15in MacBook Pro had only integrated graphics. The new models can use Intel HD integrated graphics (which shares 256MB of main memory with the CPU) for general-use applications. But for applications that require more horsepower, the system can use its discrete Nvidia GeForce GT330M graphics, with 256MB of dedicated graphics memory.

Not only are the graphics processors new to these systems, there’s also a new automatic graphics switching technology developed by Apple that looks for frameworks used by individual apps at launch (such as OpenGL and Core Animation) to decide when to switch from its energy-sipping integrated graphics to the higher-powered GT330M graphics processor. Previously, a user had to decide which graphics to use and switching between them required logging out and back into OS X. One interesting note about the automatic switching: any application that uses the required frameworks can trigger a switch from integrated to discrete graphics.

Also new is support for inertial scrolling on the Multitouch glass trackpad. If you have an iPhone, iPod touch, or iPad, the scrolling works the same way: swipe your finger up or down to scroll through a document, and the momentum continues the scrolling until it slowly stops. An Apple representative said that this feature is unique to the new MacBook Pros and is not available through a software update on older Mac laptops.

The 15in MacBook Pro’s Mini DisplayPort can now output multichannel audio as well as video. When using this port, make sure you are using a Mini DisplayPort to HDMI Adapter that supports the new MacBook Pro’s audio and video signals.