What determines whether the RAM on an i7 mother-board runs as dual- or tri-channel memory? Is there a difference between RAM sticks, or is the only difference in how they are placed in the motherboard slots?

The Dell XPS desktops that have Core i7 can run as dual-channel when they have DIMMs in four slots, with 4GB or 8GB RAM. The same machine can run as tri-channel with DIMMs in three slots for a total of 3GB, or in six slots for a total of 6GB or 12GB (though I don’t know who needs 12GB of RAM.)

Could the same 2GB sticks be used in dual- or tri-channel machines depending only on how they are placed in the slots?

Harry, there is no difference between dual-channel and tri-channel DDR3 DIMMs. The same RAM will work in dual-channel Core 2 boards and triple-channel Core i7 boards. If you have enough DDR3 DIMMs to run tri-channel, the Core i7 board will run them that way. If you put them into just two channels, the board will run them in dual-channel mode.

If you run in dual-channel mode and later want to add RAM, make sure the additional DDR3 DIMMs you buy have the same clock speed, voltages, and timings as the ones you already have. When possible, in fact, get the same model number from the same vendor as the DIMMs you already have.

SUBMIT YOUR QUESTION Are flames shooting out of the back of your rig? First, grab a fire extinguisher and douse the flames. Once the pyrotechnic display has fizzled, email the doctor at doctor@maximumpc.com for advice on how to solve your technological woes.