Dual-Channel Mode Doubles The Data Rate, Or Is Twice As Fast
This is another misconception. The DRAM itself is DDR (double data rate), so it runs at double the clock frequency (800MHz DRAM has a 1600 MT/s data rate). When you put two DIMMs in dual-channel mode, the DRAM goes from operating as an individual 64-bit device to working together and being seen by the MC as a single 128-bit device. Theoretically, that would double the bandwidth, but in actuality, it provides a performance boost of only 20 to 50 percent on Intel CPUs, and a little less on AMD rigs.
I’ve written this with input from many Tom's Hardware forum members—too many to mention individually. I’d also like to thank the fine people at Corsair, G.Skill and Team Group, whose DRAM expertise and willingness to share it are much appreciated.
As always, comments, criticism and critiques are welcome.