The Mac Pro "Twelve Core" 2.4 (Mid-2012/Westmere) is powered by dual 2.4 GHz Six Core 32-nm Xeon E5645 (Westmere) processors with a dedicated 256k of level 2 cache for each core and 12 MB of "fully shared" level 3 cache per processor. It also can be equipped with two 2.66 GHz Six Core Intel Xeon X5650 or two 3.06 GHz Six Core Intel Xeon X5675processors for a total of twelve cores for both of these custom configurations. By default, this model is configured with 12 GB of 1333 MHz DDR3 ECC SDRAM, a 1 TB (7200 RPM, 32 MB cache) 3Gb/s Serial ATA hard drive, an 18X dual-layer "SuperDrive" and an ATI Radeon HD 5770 graphics card with 1 GB of GDDR5 memory. Expansion includes two external 5.25" "optical" bays (one free by default), four internal 3.5" "cable-free, direct attach" hard drive bays (three free by default), and four PCIe 2.0 slots (one free PCIe 2.0 x16 slot and two free PCIe 2.0 x4 slots with the default single graphics card installed). Ports include five USB 2.0 ports, four Firewire "800" ports, dual Gigabit Ethernet, two Mini DisplayPorts and a dual-link DVI port, among others. AirPort Extreme (802.11a/b/g/n) and Bluetooth 2.1+EDR is standard.