Without getting into the technical specifications of what a dual channel RAM is, let me explain what you need to know about Dual Channel RAM while buying a laptop.
The RAM of a system is the only bottleneck in a system with a reasonably fast processor and I/O devices. A dual channel RAM utilises both the slots in the RAM to the optimum and hence provides the best speed possible.
Theoretically, a dual channel RAM increases the speed of the memory by 100%. This doesn’t necessarily translate into a higher system speed.
In order to work with a dual channel RAM, a laptop needs to have identical RAM in both the slots. For example, both the slots need to have 1 Gb RAM each making the total system RAM to be 2 Gb. If there is 1 Gb RAM in one slot and 2 Gb RAM in the other, then the system will again move to a single channel mode.
So, the important thing to remember while choosing a laptop is that it has dual channel RAM enabled, which will help you get better speeds out of the laptop.
On the Dell website, try configuring a laptop for 3 Gb RAM vs 2 Gb or 4 Gb. You will see that the RAM speed decreases from the 800 MHz FSB to 667 MHz FSB in the case of the 3 Gb RAM. This is because it doesn’t implement dual channel.
So, when you go out to buy a laptop, stick to either the standard 2 Gb of RAM or go for 4 Gb to get the best performance from your laptop.