pbelf

In a home environment not common as controlling physical access is easy. It is common in the enterprise. 802.1x is normally used where there is authentication in establishing the network connection. Its usually using a public key certificate based system. Mac filtering is sometimes put on top of this as an extra layer of security. I've configured it in a windows active directory setup where you have a domain controller, a certificate server and a radius server. The domain controller automatically pushes certificates out to domain joined machines. The network switch has 802.1x enabled and is given the address of the radius server for authentication. The radius server authenticates connection requests using the certificates and the active directory domain. Its quite cool and seamless when all setup. Best practice in a corporate environment as it stops any unauthorized devices being plugged in and getting a network connection. Totally overkill in the home.

You can get 10gbit to work on a 10m Cat5e cable. Ethernet cables are generally extremely reliable, unless its been subject of some serious physical abuse it will be fine. There is actually a minimum length in the Ethernet spec of around 1 meter. You can in theory get a bunch of specific electrical problems on very short cables. the reliability of wireless on the other hand...

The way that the power is actually delivered down the cable with 802.3af is not just a case of using some of the pins for power and some for data. The power and data are actually delivered down the same individual wires. There is actually quite a sophisticated electrical handshaking that happens at connection to work out if the device at the end of the cable supports 802.3af as sending power to device that isn't expecting it isn't a great idea. If you injector supports gigabit and I'd be suprised if there any that you buy today that don't then it won't degrade to 100Mbit.

The LGA stands for land grid array which is the style of sockets with the pins in the socket and little pads on the chip. As said the the 1151 etc is the number of pins. The physical dimensions of the chips are very similar but they are not mechnically compatible. On the side of the socket there are little notches that mate with a corresponding cut out on the chip. Intel change the location of these notches between the different versions so the chip won't sit in the incorrect socket. The heatsink connection specifications are the same between all of them. The 2011 sockets have a lot more pins because it takes a lot more connectors to support the 18 cores of the high end xeons. And more pins requires more physical space so the socket is a lot bigger. I don't think intel change the sockets to make money, sometimes new chip features require different electrical connections. It probably also makes it a lot easier to deal with compatibility between architecture revisions as it physically stops people attempting combinations of chips and motherboards that just aren't designed to work together.

Those two are so similar that it wouldn't suprise me if they are the same chip with just a few different things enabled or disabled. The list price of them both is also very similar. If stability, ECC memory and the potential for a lot of RAM is important go with the Xeon. If you want to overclock and eek out every last bit of speed get the i7.