What kind of expansion slots are provided by the "Unibody" MacBook Pro? Which have ExpressCard/34 and which have SD Card slots?

15-Inch MacBook Pro models -- "Unibody" and otherwise -- released prior to June 8, 2009 include a single ExpressCard/34 expansion slot and all subsequently released 15-Inch MacBook Pro models have SD card slots instead. All 17-Inch MacBook Pro models include a single ExpressCard/34 expansion slot.

Also see:

• What is ExpressCard/34? Is it compatible with PC Cards?
• What is the difference between ExpressCard/34 and ExpressCard/54? Speed?

Can you upgrade the processor in the "Unibody" MacBook Pro?

No. All MacBook Pro models -- "Unibody" and otherwise -- have the processor soldered to the motherboard. It is not upgradable.

What are the capabilities of the optical drive provided by the "Unibody" MacBook Pro models?

All "Unibody" MacBook Pro models have an 8X slot-loading "SuperDrive" (DVD±R DL/DVD±RW/CD-RW). This drive is capable of reading and writing dual-layer and single-layer DVD as well as CD media.

What is the maximum supported resolution for an external display connected to a "Unibody" MacBook Pro?

All "Unibody" MacBook Pro models -- regardless of release date -- support an external display at 2560x1600. However, models in the "Late 2008," "Mid-2009" and "Mid-2010" lines have a Mini DisplayPort whereas the "Early 2011," "Late 2011" and "Mid-2012" models have a "Thunderbolt" port instead, which is backwards compatible with Mini DisplayPort and works with Mini DisplayPort-equipped displays.

Please note that Mini DisplayPort and Thunderbolt both only support VGA, DVI, dual-link DVI and HDMI with adapters.

Also see:

• What is "Mini DisplayPort"? Is it an industry-standard? How is it different from Mini-DVI and Micro-DVI?
• What is "Thunderbolt"? Is it an industry standard? What advantages does it offer? Are there any disadvantages?

Which MacBook Pro models can pass an audio signal via Mini DisplayPort and which models cannot?

The Mini DisplayPort provided by the "Mid-2010" MacBook Pro models -- the MacBook Pro "Core 2 Duo" 2.4 13-Inch, "Core 2 Duo" 2.66 13-Inch, "Core i5" 2.4 15-Inch, "Core i5" 2.53 15-Inch, "Core i7" 2.66 15-Inch and "Core i5" 2.53 17-Inch -- can pass an audio signal, so it possible to use a Mini DisplayPort to HDMI adapter without the need for a second USB adapter for audio when connected to a device that supports audio via HDMI (like an HDTV). Earlier MacBook Pro models do not have this capability.

Also see: What is "Mini DisplayPort"? Is it an industry-standard? How is it different from Mini-DVI and Micro-DVI?