I find it so strange, before I was on 3 x 2gb of 1600Mhz ram with dram volt of 1.65v at timing 8.8.8.24 and got 4Ghz with temp of 85, 85, 82, 83 (1 hour full load) with all case fans on low speed. Now, I had decided to take memory ram out and replaced with 6 x 2gb of 1333Mhz ram with dram volt of 1.50v at timing 9.9.9.24 and got 4Ghz with temp of 79, 79, 76, 77 (1 hour full load) with all case fans on low speed. Big huge difference on core temperature between 6gb 1600Mhz 8.8.8.24 1.65v and 12gb 1333Mhz 9.9.9.24 1.50v as it so strange indeed.
I was surprise that 12gb of ram was accepted on overclocked 4Ghz.