@smiles77, in general I'd say no.
The main reason for going 2x1 instead of 1x2 is to get the dual channel memory interface working. Both 2x2 and 4x1 will operate in dual channel mode, so there is no significant performance difference if all else is equal.
As for the overclocking side, there's a bit of push and shove there. I never really ran with 4 sticks, but in general 4 sticks are considered less stable than 2. However, having said that, in general bigger sticks are lower performing and higher cost per capacity at top end performance. But for 99%+ of people this is an insignificant consideration. If you're getting mainstream speeds, higher capacity gives more flexibility.
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