Asus p7p55d randomly doesn't recognise all 4GB

[ea25]

Specs :

Lynnfield i5 750 on asus p7p55d 1156 sock. Corsair XMS3 4GB (2x2GB) PC3-12800C9 1600MHz DDR3

The system is overclocked and bypassed intel burn test reaching max temps of 70 degress with the following settings :

Intel Speedstep - Disabled
Intel TurboMode - Enabled
CPU Ration - x19
Bclk Frequency - 200
PCI-E Frequency - 100
Dram Frequency - DDR3-1600mhz
Dram CAS - 9
Dram RAS-CAS - 9
Dram RAS-PRE - 9
Dram RAS-ACT - 24
All other dram timings settings - Auto
CPU Voltage Mode - Manual
CPU Voltage - 1.35
Dram Voltage - 1.6v

System seems to be very stable when running windows however it doesn't always recognise all 4Gb of ram installed (only recognises 2). This happens randomly so I can't really tell what is causing the problem. Another thing I notice is that when the i press the restart button it doesn't respond immediately, there is like a 5 seconds delay and then it restarts. Would like some help please thank you

 

[evongugg]

Are you aware of this?

P55 Extreme Overclockers: Check your sockets!

http://www.anandtech.com/mb/showdoc.aspx?i=3661

 

[evongugg]

Please see more here:

http://www.tomshardware.com/forum/268319-28-overclocking-chipsets

 

[ea25]

THanks for the link evongugg but i don't it is the socket. I removed one of the chips and rebooted a dozen of times with overclocked settings and everything went fine so I don't think it is a socket issue. Than i replaced the chip with the other one in the same slot and after to reboots and intel burn tests the pc started playing one again. POST randomly stops and mobo ram light lights red. Might it be an issue of a defective chip ?