The Asus Z7S WS

The Asus Z7S WS features dual LGA771 sockets that support Intel Xeon 5000, 5100, and 5300 series processors of both the dual and quad-core varieties. The Z7S WS is built around the Intel 5400 and ESB2E chipset and supports 1600MHz / 1333MHz / 1066MHz / 800MHz front side bus speeds, it has six Fully-Buffered DDR2 DIMM slots, and a pair of Marvell 88E8056 Gigabit LAN jacks with teaming functionality. The Asus Z7S WS’ expansion slot configuration consists of two PCIe 2.0 x16 slots, one PCIe x16 slot with an x8 electrical connection, and single PCIe x1, PCI-X, and PCI 2.2 slots. The dual x16 PEG slots are a differentiating factor for the Z7S WS because Intel’s D5400XS only supports PCI Express 1.1. The D5400XS, however, is outfitted with NVIDIA PCI Express switches which enable SLI, something the Z7S WS lacks. Also note that the Asus Z7S WS requires standard LGA771 heatsinks, whereas Intel’s Skulltrail mobo will work with a wider variety of LGA775 CPU coolers. We should also point out that the Z7S WS features a digital VRM, which significantly clears up the area around the CPU sockets and the PCB is "only" 12" x 10.5", which is much smaller than the DX5400XS.