Stabilizing i7 uncore - help appreciated

[Fireball]

Stock settings Prime stable @ stock settings (optimized defaults) running blend for 10 hours.

I think I really need to go back to square one for overclocking. There must be some setting / voltage I must be missing, because yesterday out of boredom I dropped the memory multiplier to 6x (runs default @ 8x) and uncore to 13x, and all of a sudden the rig became unstable (fail Prime blend within 2 minutes).

The odd thing is that I drop the memory into my brother's computer, which is running a Gigabyte board as well (I believe the DS4?), and it will run at rated speeds no problem simply with VTT bumped to 1.35 and VDimm bumped to 1.66.

I'm less inclined to think that the problem is caused by a bad IMC itself, since I would expect the rig to remain stable when I drop the mem multi to 6x and uncore to 13x while staying at the same BCLK...

I'll check the memory voltage settings tomorrow.

[Fireball]

Apologies...been on call.

Ram settings:

Performance enhance: Standard
CAS latency - 8
tRCD - 8
tRP - 8
tRAS - 24
CMD Rate - 1T
Channel interleaving - Auto
Rank interleaving - Auto
tRC - Auto
tRRD - Auto
tWTR - Ato
tWR - Auto
tWTP - Auto
tWL - Auto
tRFC - Auto
tRTP - Auto
tFAW - Auto
B2B CAS Delay - Auto
Round trip latency - Auto
All turnaround settings on auto