ASUS P9X79 + G.SKILL F3-10666CL9D-8GBXL + Intel Core i7 3820 Memory problem?

[mix2ra]

Hi
I am having some memory issues which I have problems investigating.
I got BSOD very often + sometimes my computer just freezes. I thought that this could be a memory problem so I ran the memTest86 and memTest86+ (free open source).
The first ran on memTest86+ gave 5 errors around 13Gb address, the next pass gave 10 errors also around 13Gb addresses but a bit different.
memTest86 first run did not found any errors running on one CPU. When I switch to all CPUs test (sequential) I got also problems around 13Gb address.
OK, so I start to test each module individually but they were all OK (maybe the test was to short, I did only one pass for each module).
Then I tried to test the whole set again, the first test gave me about 900 errors, so I restarted and run it again – no errors.
I tried to test one pair at a time : One pair is OK, the other shows some errors (sometimes).
To me it looks a bit strange as the testing results seems to be a bit unstable, which makes me bother is it the memory modules, or maybe the mobo or the CPU?
ASUS Reported on their QVL that F3-10666CL9D-8GBXL are compatible with P9X79
G.Skill does not report ASUS P9X79 as compatible

My question is what would you suggest to discover the problem?
Are my RAM module compatible with my mobo?
Is there anyone having the same CPU + mobo + RAM Configuration?
Anything that would help.

Regards,
Sebastian

My configuration is as follows
ASUS P9X79 WS (Newest BIOS 4505)
G.SKILL F3-10666CL9D-8GBXL (2 x 2Kits = 4 x 4GB)
Intel Core i7 3820 3,60
Windows 8.1 64-bit
Thermal Take PSU 1200W
NVidia Quadro K2000
All settings in BIOS are set to defaults / auto , no OC configuration

[mix2ra]

I am testing with memSet86 V5.
Decided to start with all 4 modules inserted and test again.
I set the factory settings for the DRAM modules in BIOS manually.

When testing in multi CPU sequential mode I get tones of errors (about 2000)
When testing with single CPU, Multi CPU in Parallel and Multi CPU Round Robin I have NO errors (so far). Only in sequential mode.

What could it mean?

Regards,
Sebastian

[GSKILL TECH]

Try one module at a time or one kit at a time first to see if one performs differently. This way you can isolate the issue and make sure it is not a defective memory stick.

It can also be a matching problem between the two kits so this kind of testing needs to be done. With all four modules installed, it doesn't tell us what the problem may be.

Thank you
GSKILL TECH