Arctic Silver 5 really helped.
I removed the stock thermal compound and applied Arctic Silver 5 on the Dark Knight heatsink plate. I made sure that all gaps are covered. The Dark Knight heatsink design is a direct pipe contact with the cpu so there is some gap between the pipe and the plate. It is important that thermal paste fills all those gaps.
My cpu overclocked at 4Ghz now idles between 40C and 45C. Under full load with Prime 95 test for 15 minutes, the cores stay under 80C.
They used to idle around 50C and reach 100C under load.
I removed the stock thermal compound and applied Arctic Silver 5 on the Dark Knight heatsink plate. I made sure that all gaps are covered. The Dark Knight heatsink design is a direct pipe contact with the cpu so there is some gap between the pipe and the plate. It is important that thermal paste fills all those gaps.
My cpu overclocked at 4Ghz now idles between 40C and 45C. Under full load with Prime 95 test for 15 minutes, the cores stay under 80C.
They used to idle around 50C and reach 100C under load.