I need to replace my existing 16 GB of RAM

[SkyDan]

I need to replace my existing 16 GB of RAM - G.SKILL Sniper F3-12800CL7T2-24GBSRD. XMP became unstable and fails memtest86 every time. I am thinking getting a faster memory kit such as CORSAIR Dominator Platinum CMD16GX3M4A2400C11 and downclocking it to 2133 while tightening timings. Will this work? According to the manual 2133 is the highest speed. Asus website says 2200 that will be downclocked to 2133 due to CPU limitations. I need to know if fast memory is stable when downclocked.

Thank you.

Rig Specs:
I7-2700K @ 4900Mhz
Asus Maximus IV Extereme-Z
EVGA Tinan X Hydro Copper
All liquid cooled

 

[Tradesman1]

When did it become unstable? That's a six stick set of DRAM and you are only using 4 of them so the timings aren't gong to be optimal, especially on a Z68 (those never did get good BIOS update support since they were so short lived) - what are they currently running at? Also are you testing the DRAM with Memtest on each individual stick or on all four sticks together (same as above applies, not using the full set that the programming is based on for the DRAM).