i never had issues with clocking samsung on UD5H or UD3H, both got same speeds up to 2800+. the GD65 was a little weaker for me with samsungs, even PSC it was a touch weaker.
however when i bench LN2 i get 51 often below -130 then i can only "bench" with 1 stick. tested 2 boards and 2 different CPU's.
i use vaseline in my slots. mebe i should clean a bit. Air is fine tho