Adding RAM... leave the original stuff in?

[Nealio]

I currently have a Phenom II system on a Gigabyte GA-MA790XT-UD4P motherboard.

I have 4Gb of Corsair XMS3 1600MHz memory as 2X2Gb sticks.

I want to add more RAM so the question is:

If I buy another 2X4Gb sticks (either the same XMS3 model or not) is there any disadvantage to leaving the current 4Gb in place to make a total of 12Gb with all 4 slots populated, or would it better to run just the 2 new 4Gb sticks?

I guess the question boils down to: does it still run in 'dual channel mode' if all 4 slots are populated (with different capacities)?

 

[Nealio]

Excellent, thanks.

Also, I want to upgrade to an i5 system in the not-too distant future, is the XMS 3 memory good to use with intel or should I choose a different type to ensure compatibility and performance?

 

[Nealio]

Great, thanks... Time to hit the credit card up then, fancy an SSD too