I have a gigabyte p55m-ud2 motherboard and i have 2x2gb of ram inserted in dual channel configuration.
The problem i have is that my heatsink covers one of the ram slots, which is the third slot.
My question is that if i insert 1 ram stick into the 4th slot will that disable the dual channel on the sticks in slots 1 and 2?
I know inserting the 1 ram stick in slot 4 will not be in dual channel because you have to insert in pairs but will it affect the other 2 sticks that are inserted in the first 2 slots?

Thanks for letting us know that you've RTFM.
Better late than never I suppose, at least I won't have to waste any more time on you.