System hang - freeze when installed 2 set KIT ram

Question

Original my system:

• MOBO: GA-Z68XP-UD3R (rev 1.3)
• CPU : Intel Corei7 2600 (3.4GHz)
• VGA : GV-R6750OC-1GI
• POW : ACBel 510W
• CPU-Cooler: Cooler Master Hyper 412 Slim
• RAM:: Kingston 4GB (2x2GB) 1866 KIT - (KHX1866C9D3K2/4GX)

It's first build and I have been using it for several months and my system worked fine.

But, when I bought the exact same memory, from the same vendor and installed it, Windows 7 system started to hang.

I even re installed Windows 7x64 and yet Windows 7 freezes randomly.

I has tried bumping up the RAM voltage, fixed DRAM TIMING as per specs (Profile1-1866: 9-11-9-27 or AUTO).

But the bug still occurs!

After installing a set of KIT 4GB (2x2GB),system is working fine.

If I install 2 sets of KIT 8GB (4x2GB) system hangs and freezes randomly!

Is there anyway to make it work?

Answer 1

Your question is awfully specific and I doubt it will help anybody else as you asked it. But let me answer it in a more generic way.

Q:
I have a system a pair of memory DIMMS. These work. If I put in a different pair they also work.
If I put both in they do not work.

A:
If you load the memory system with more modules you put it under more stress.

Your CPU supports the following: Memory Types: DDR3-1066/1333 (Source: Intel).
If you run these at 1866 then you are out of spec for your CPU. You might get lucky and it might work. It also might not work. You just added more stress to the memory subsystem. Guess what...