X58 12GB RAM - Prime95 Instability

[earlydoors]

Hi

I have recently added 3 further DIMMS on my Gigabyte x58 mobo to take the total RAM from 6GB to 12GB

Specs are:

Mobo: Gigabyte EX58-UD4
CPU: Core i7 920 D0 at stock 2.66Ghz
RAM: OCZ Gold CL9 1333Mhz 6x2GB = 12GB

I tested using P95 blend, which initially showed rounding errors within a few minutes on all 8 workers. I then have loosened the RAM timings to 9-9-9-28 and upped the RAM voltage to 1.66V (they are rated for 1.65V)

I also have upped the QPI/Vtt voltage incrementally.

It appears that small, stepped increases to the QPI/Vtt voltage is increasing the stability on P95, although overnight the workers found rounding errors on all but one core, within 3-5 hours.

Is my strategy correct? to hold all other adjustments and slowly increase the QPI/Vtt? Will this increase the stability

For reference, I ran Memtest86 4.3.6 and found no errors.

I am monitoring temparatures using RealTemp and they are acceptable.

Currently voltages are:
Vcore 1.2625 (stock)
QPI/Vtt 1.3135
IOH Core 1.100 (stock)
DRAM Voltage: 1.66V

Please let me know if I am missing something, or any advice/thoughts are welcomed.

many thanks

 

[Burpo]

I doubt you need to bump up voltage to the RAM (I use 1.64) and QPI shouldn't need to be any higher than 1.34. I think you're on the right track.

 

[paul878]

I would set the memory to 800mhz and see if the error goes away.

 

[tarmc]

Its definitely a voltage issue vtt may need to be at 1.35 ioh 1.2-1.3. Had simular issues with 12g (6x2g) raising volts fixed. Also bump it up to 1600