1.Two 2.26GHz Quad-Core Intel Xeon "Nehalem" processors
6GB (6x1GB) of 1066MHz DDR3 ECC memory
640GB Serial ATA 3Gb/s 7200 rpm
18x SuperDrive (DVD±R DL/DVD±RW/CD-RW)
NVIDIA GeForce GT 120 with 512MB GDDR3 memory
2.Two 2.8GHz Quad-Core Intel Xeon processors
2GB (2 x 1GB) of 800MHz DDR2 ECC fully buffered DIMM
320GB Serial ATA 3Gb/s 7200-rpm hard drive
16x SuperDrive (DVD±R DL/DVD±RW/CD-RW)
ATI Radeon HD 2600 XT 256MB (two dual-link DVI ports)
3.One 2.66GHz Quad-Core Intel Xeon "Nehalem" processor
3GB (3 x 1GB) of 1066MHz DDR3 ECC memory
640GB Serial ATA 3Gb/s 7200 rpm
18x SuperDrive (DVD±R DL/DVD±RW/CD-RW)
NVIDIA GeForce GT 120 with 512MB GDDR3 memory