Be careful on what ram you go for on the UDH5 as I bought this mobo but my 2133 mhz corsair vengeance blue ram only detected at 1333 mhz
How's it going Propete, I'm not sure if you resolved your issue as of yet, either way, the following may provide assistance to you..
I have the GA-Z77X-UD3H with the Corsair vengeance 1600, I also received the exact speed 1333 mhz, however, within the Bios of my MB, I'm able to go into the mem settings (of the top of my head, I think it may be the MIT part of the BIOS) and configure the mem speed, doing this i have total control of speed and other variables also..
I7- 3770K 3.5
16GB Ram Corsair Veng 1600
OCZ 120GB Vertex3 SSD
Sata2 HDD 2TB