<P> The CPU in the first - generation MacBook Air was a custom Intel Core 2 Duo Merom that was 40% of the size of the standard chip package . For models of late 2008, the CPU was replaced with a low - voltage Penryn chip with 6MB of cache, running on a 1066 MHz bus . </P> <P> MacBook Air components are officially non-user - replaceable, though third - parties do sell upgrade kits for the SSDs . The flash memory and battery are enclosed within the casing, with RAM soldered onto the motherboard . The flash memory, difficult to access, has a 128MB cache and a mSATA connection (updated to a proprietary PCIe interface) to the motherboard . </P> <P> Apple incorporated several features in the design of the MacBook Air, such as the reduction of lead to make it more environmentally friendly . The MacBook Air contains no BFRs and PVC wiring, meets Energy Star 5.0 requirements, has a recyclable enclosure, and is rated EPEAT Gold . Its display is made from arsenic - free glass, and contains no mercury . To reduce the computer's size and weight, several features were sacrificed . It was Apple's first notebook since the PowerBook 2400c without a built - in removable media drive . It also omits a FireWire port, Ethernet port, line - in, media card slots (except the 13" 2010 through 2015 models, which have an SD card slot), and a Kensington Security Slot . </P> <P> To gain optical drive features, users could either purchase an external USB SuperDrive or other brand, or the bundled Remote Disc software, only for browsing or software installation to access the drive of another computer wirelessly that has the program installed . It can also be used to reinstall the system software from the included installation DVD . Remote Disc supports NetBooting, so the Air can boot from its installation DVD in another computer's drive, which requires Remote Install Mac OS X to be running on that computer . The software does not allow playback or information of DVDs, CDs or installing Windows . For these features, an external USB drive is required . More recent versions of OS X replaced the installation DVD with a USB flash drive containing the software, eliminating remote installation . </P>

Does a macbook air have an ethernet port