The price point will be the most significant difference between quad-channel and dual-channel RAM. Thus, the applications of the units will be different. The other primary difference is the speed of the units.
Quad-channel RAM is not necessarily that much faster than your current dual-channel setup. This is because when upgrading to quad-channel RAM, you’re increasing the memory bandwidth, not the clock rate.
The best way to put it is that if you have the option to install quad-channel RAM already, you might as well. But, suppose you’re looking to purchase or build a new system, particularly a very compact one.
Yes, you can mix dual and quad-channel RAM sticks. However, doing this will cause the motherboard to run exclusively in dual-channel mode, as a number of the sticks will be unable to support quad-channel mode.
– Quad-channel RAM has twice the memory bandwidth of dual-channel RAM. – Quad-channel RAM puts more pressure on the motherboard’s memory controller.