You must use what the asus board supports and what they tell you to use:
8 x DIMM, Max. 64GB, DDR3 2133(O.C.)/2000(O.C.)/1866*/1600/1333/1066 MHz ECC, Non-ECC, Un-buffered Memory **
Quad Channel Memory Architecture
*For Registered Memory, Max. 256GB DDR3 1866/1600/1333/1066/800 MHz
** Refer to www.asus.com for the Memory QVL (Qualified Vendors Lists).
I am using 2x 8gb ddr3 hyperx at 1333mhz as far as I understand it should work. Or do I need to populate all 8 dimms? Does the 2670 REQUIRE ecc memory or it works with ecc and non ecc? Still not sure but thank you for your quick answer.
No, the e5-2670 does not require ECC.
If your memory meets the specifications of the motherboard, then it should work. I will leave that to you to determine.
No, you do not need to populate all 8 slots.
Support for these questions is best obtained from Asus.
Ok thank you very much!