corsair XMS3 not running at DDR3-1600

[ContainedComa]

I got a new 8gb stick of corsair xms3 ddr3 1600 cl11 ram to add to my 4gb stick of 1600 cl9.

However, I get BSODs if I try to run it above 1333, after enabling XMP.

Do I have a bad stick?
I've just started memtest which says it is running at ddr3-798 (I think - I've never used it before)

I have an i5-4670K (stock) on an Asus h81m-e.

Please help!

 

[ContainedComa]

Memtest (start):

 

[ContainedComa]

I ran memtest with just the new 8gb stick in and immediately got thousands of errors. I will return it as it appears to be faulty.