The following figure also shows a 2+2 & 4+4 configuration in dual channel, illustrating that the paired slots will continue to run in dual channel mode as long as the capacities across channels match (thus it's 6 GiB per channel in dual-channel configuration). That 2 GiB + 2 GiB = 4 GiB is a coincidence. My 5600X with 4 sticks can only do 1833 stable. In other words, the 4 GiB size of the other module is just for illustration that the sizes need not match in that case. Solid State Soul ( SSS ) said: filling all dimm slots increases the load on the memory controller and reduce overclocking headroom resulting in problems with some high frequency XMP kits. In the example, that means 4 GiB dual channel RAM from the 2+2 configuration plus 4 GiB of single channel RAM from the single 4 GiB RAM module. (DIMM1 and DIMM2, as well as DIMM3 and DIMM4, seem to be paired, so you cannot install matching size modules into DIMM1 and DIMM4, for instance, despite them technically being on different channels as well.) Extra, unpaired RAM modules will run in single-channel mode, no matter their capacity. In order to make use of dual-channel operation, both channels should have a RAM module with matching capacity, hence the manual suggests installing two matching-capacity modules into DIMM1 and DIMM2.

Supports one pair of modules inserted into either the yellow slows or the black slots as one pair of Dual-channel memory configuration 3.

Whats happening when I turn it on is the CPU light turns on. In the figure, DIMM1 and DIMM3 are on channel A, whereas DIMM2 and DIMM4 are on channel B. Supports one module inserted in any slot as Single-channel memory 2. 1 Swapping RAM, using new RAM, and putting it in different slots. DIMM slots of the same colour indicate different channels.

Dimm slots 3 yellow 1 black