View Full Version : AsRock P55 Extreme/8GB RAM: COLD boots find only 4GB, 2 modules

09-13-2010, 11:47 PM
Hi all,
I've recently bought an AsRock P55 Extreme, fully populated with 4x2GB modules RAM Corsair 1600 MHz cas 9, running at the safe value of 1333 MHz, 9-9-9-24. I've installed a Core i7 860 cpu on it and I do not overclock.
At cold boots the motherboard does recognize only 2 modules, 4GB total. At hot boots it finds all modules, 8GB total.

This is what happens:

Case A)
I power on the psu and boot the pc. At cold boot the motherboard only sees 4GB and that's put on screen, it reads 4088MB:


I let the boot continue and, when in windows 7, I can read:

http://img62.imageshack.us/img62/594/ramcpuztm.th.png (http://img62.imageshack.us/i/ramcpuztm.png/)

and in Linux I find that situation:

http://img844.imageshack.us/img844/3327/ramlinux.th.png (http://img844.imageshack.us/i/ramlinux.png/)

From the POST to the OS login the memory used is 4GB.

Case B)
The very moment I read 4088MB on POST during the cold boot I press Ctrl+Alt+Canc and let the system reboot. Now the pc performs a hot boot and the memory is correctly recognized, the POST reads 8184MB:


windows 7 and cpu-z read:

http://j.imagehost.org/t/0981/8gb_win.jpg (http://j.imagehost.org/view/0981/8gb_win)

and Linux too uses all 8GB ram:

http://j.imagehost.org/t/0666/8GB_Linux.jpg (http://j.imagehost.org/view/0666/8GB_Linux)

Now let's try an intermediate step in Case A).
After the POST reads 4088MB I press F2 and enter the BIOS setup utility where I can see (with amazement, I admit...), a system summary where all 4 slots are correctly indicated as populated, the total amount of memory is 8GB and it can determine the DRAM frequency too:


I flashed my bios with almost every official bios version from AsRock, from 1.60 to the 2.70 one, with no improvements at all. I tried configuring the bios, specially the dram timings, with no effect: at every cold boot the system only manages to find 2 modules/4GB and I need everytime to reboot in order to let it sees all of 8GB.

As suggested by AsRock Support I performed a list of test:

- I disassembled and reassembled the whole system, from cpu to memory;
- I tested every single ram module with memtest+ and they all passed it;
- I switched ram modules and dimm slots with every possible combination;

everything goes nowhere, the cold boot can't see 4 modules, the hot boot does.

What do you suggest guys?
Thank you for reading and sorry for the long post ;)