Via KitGuru.
Info on X99 and Haswell-E:
The new Core i7 Haswell-E 5000-series central processing units will be compatible with Intel X99 chipset as well as LGA2011-3 socket. The platform will be tailored for enthusiasts, so it will support very flexible tuning and overclocking capabilities, up to five devices in PCI Express 2.0/3.0 x8 mode (four graphics cards and one enthusiast-class solid-state drive in PCIe card form-factor), ten Serial ATA-6Gb/s ports, up to six USB 3.0 ports (14 USB ports in total), various Intel technologies like Rapid Storage, Rapid Recover and so on.
Previously it was believed that Intel will introduce the Core i7 Haswell-E 5000-series CPUs in the third quarter of 2014, in August or September. However, it looks like the company decided to speed up the things quite a bit: the new high-end desktop (HEDT) platform from Intel will be unveiled at Computex Taipei 2013 trade-show and will reach the market shortly after that.
Info on X99 and Haswell-E: