Is all DDR3 considered triple channel? The reason I ask is as part of seeing the dev release of Windows 8 and it's utilization of UEFI I started researching motherboards for a potential upgrade near the end of the year. The board I am on now has DDR3 and it has six slots but it seems like almost all new boards only have four slots, yet are asking for DDR3. That doesn't make sense to me.
DDR3 is a memory standard that is twice as fast as DDR2.
Dual and triple channel memory is not a feature of memory per se, but it is a feature that requires a compatible motherboard and processor.
Dual/Triple channel in its simplest form is breaking up the data the memory needs to use in to two or three chunks instead of one so that each part can be done at the same time - increasing speed.... If you want to know more in detail, read the Wikipedia entry.
In addition, you usually require memory modules to be the same as having different specifications can degrade performance/have undesirable effects.
"Triple channel" is a feature of the memory controller and system configuration, not the memory sticks themselves. Most motherboards that have six slots support triple channel, with up to two memory sticks on each channel. Triple channel mode will typically only work if each channel has the same amount of memory on it.
If a board has four slots, it is most likely dual-channel. That means the memory controller has two channels and can interleave requests across them for greater performance. Dual-channel memory controllers have existed with pretty much every memory technology, not just DDR3.
The 3 in DDR3 just means it's the third generation of DDR memory. It has nothing to do with the number of channels the memory controller supports.