The board will not run in triple channel mode (simply not possible), but as long as you can install all 3 DIMMs, you should be fine (your mobo has 4 memory slots, right?). However, since your aren't necessarily installing in matched pairs, you may only be working in single channel mode. If you only use 2 of them, you would be able to run in dual channel mode. Understand? Good luck!
As above said you would be running them in single channel mode if you run all three of them.
Do not be worried about running them in single channel mode; the performance difference between single, dual and triple is very small in basically every application.
Conclusion: There will be no performance issue, run all three sticks.
Hope that helps.
there are some threads in this forum that are saying that running 3 dimms may allow 2 to run in dual channel config and the 3rd as a single channel config
I'm running 3 dimm's right now and cpu-z says it's dual channel
there doesn't seem to be any consensus, but I guess the end point is that put all 3 sticks in and see if it's better than 2!?
other threads however are saying you're better off leaving the 3rd stick out because dual channel is so much more superior (assuming of course that 3 sticks will make them all run as single channel)