Dual channel gives twice the memory bandwidth but requires two identical sticks of RAM.
Hey there,
So this statement isn't entirely accurate. You can of course use two different 8gb sticks (providing they work together) to achieve Dual Channel. Dual channel does not require a matching kit. However, for best compatibility and stability, having a 2 x matched kit is the way to go. Dual Channel is not dependant on the ram being in a kit though.
So when people are telling you that putting in an identical 8GB stick might not work, they're talking about dual channel. It'll definitely work in single channel, and you'll still get better performance than with a single 8GB stick, but it won't perform as well as 2x8GB in dual channel.
As above. If both sticks work together (which is possible) then dual channel is possible. A good example of this would be in laptops (but also desktops). You could have a Corsair 2933mhz SO-DIMM, and another Samsung 2933mhz SO-DIMM with same timings. They will often work together (laptops are much more forgiving for mixing ram) with no issues, and of course will be in dual channel mode.
Sometimes though, the DIMMs/SO-DIMMs will default to the lowest timings or clock speed of the slowest DIMM.
So with the above example of Corsair 2933mhz DIMM which might be CL18, and the Samsung 2933mhz DIMM being CL16, they will both run at the slowest, in this case the CL18 timings.
On desktops, you can play around with timings, voltage and SOC to help make ram that doesn't work together, and get them to work together. But, it takes a lot of tinkering around with sub timings, and this can be a right pain in the butt.