After installing your memory modules the final step is to check if they are really operating under dual-channel mode.

Currently most motherboards will display this information on POST, which is that screen that appears right after you turn on your computer, showing some information about your system. Look for phrases like “Dual Channel” and “Single Channel”, see Figure 9.

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Figure 9: PC with dual channel mode correctly enabled (see “at Dual Channel”).

Another way to check this is by running a hardware identification utility. We recommend running CPU-Z and checking memory information presented on its Memory tab, see Figure 10. You can see if dual-channel is enabled under “Channels #”, which should report “Dual”. On this same screen you can check the current real memory clock rate and timings. Keep in mind that the real clock rate is half of the announced memory clock. In our example (Figure 10) the memories were being accessed at 333 MHz, i.e. “667 MHz”. This is a good place to check if your memories are being accessed at their full speed. If not, you need to check to see what is wrong (usually a misconfiguration on the motherboard setup or a limitation from the CPU or chipset – for example, if you have an Intel-based PC and your chipset only supports up to DDR2-677 don’t expect to get 800 MHz with your DDR2-800 memories!). Tip: some Athlon X2 processors have a problem where memories can’t be accessed at their full speed, click here for more information.

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Figure 10: PC with dual channel mode correctly enabled (see “Dual”).