is itself held in place by two "captive" thumbscrews that can be loosened by hand without tools and will not fall out of the case. On the original Mac Pro introduced in August 2006, the PCIe slots can be configured individually to give more bandwidth to devices that require it, with a total of 40 "lanes", or 13 GB/s total throughput. When running Mac OS X, the Mac Pro did not support SLI or ATI CrossFire, limiting its ability to use the latest "high-end gaming" video card products; however, individuals have reported success with both CrossFire and SLI installations when running Windows XP, as SLI and CrossFire compatibility is largely a function of software. The bandwidth allocation of the PCIe slots can be configured via the Expansion Slot Utility included with Mac OS X only on the August 2006 Mac Pro. The Early-2008 and later Mac Pros had PCIe slots hardwired as in the accompanying table. External connectivity For external connectivity, the Mac Pro included five USB 2.0 ports, two FireWire 400 and two FireWire 800 (Late 2006 until Early 2008), respectively four FireWire 800 (Early 2009 until Mid 2012) ports. Networking was supported with two built-in Gigabit Ethernet ports. 802.11 a/b/g/n Wi-Fi support (AirPort Extreme) required an optional module in the Mid 2006, Early 2008 and Early 2009 models, whereas in the 2010 model and later Wi-Fi was standard. Bluetooth also required an optional module in the Mid 2006 model, but was standard in the Early 2008 and newer models. Displays were supported by one or (optionally) more PCIe graphics cards. More recent cards featured two Mini DisplayPort connectors and one dual-link Digital Visual Interface (DVI) port, with various configurations of on-card graphics memory available. Digital (TOSlink optical) audio and analog 3.5 mm stereo mini jacks for sound in and out were included, the latter becoming available on both the front and back of the case. Unlike other Mac computers, the Mac Pro did not include an infrared receiver (required to use the Apple Remote). In Mac OS X Leopard, Front Row could be accessed on the Mac Pro (and other Macs) using the Command (⌘)-Escape keystroke. Case From 2006 through 2012, the exterior of the Mac Pro's aluminum case was very similar to that of the Power Mac G5, with the exception of an additional optical drive bay, a new arrangement of I/O ports on both the front