1U space-saving design Quad-Core Intel Xeon X5472 up to 3.0 GHz and up to 1600 MHz front-side bus or Dual-Core Intel Xeon X5272 up to 3.40 GHz and up to 1600 MHz front-side bus Up to 64 GB Fully Buffered DIMMs 667 MHz via 16 DIMM slots 1 PCI-Express x16 Gen 2 full-height/full-length or 1 PCI-Express x8 Gen 1 low-profile/half-length