870 Extreme3 Dual Channel Memory Problem

[PaulChan11]

Hi Everyone,

I have a 870 Extreme3 MB running 1.6 BIOS, AMD 555BE. Here is the problem I am having.

1 - When I have the 2 sticks of OCZ DDR3 PC3-12800 (2 x 2GB kit) in memory slot A1 and B1 (blue slots). BIOS will detect as "Dual Channel Mode" in POST, however the computer will only boot after the "Memory Clock" is reset to "400Mhz". Windows would start, but run unstably. CPU-Z confirms the 400Mhz clock. RAM model #OCZ3BE1600C8LV4GK

2 - When I move the 2 sticks of RAM to memory slot A2 and B2 (white slots). Same behavior.

3 - When I move them to slot A1 and A2 (one blue one white). BIOS will detect as "Single Channel Mode. "Memory Clock" can be set to 800Mhz, and Windows would run stable.

I thought the RAM was faulty, so I went out and bought 2 more sticks of Corsair DDR3 PC3-12800 (CMX4GX3M2A1600C9), and the result was exactly the same. There is also no difference whether UCC is enabled or not.

Now, I am not crying over Single / Dual Channel mode, for I know the difference is very little, however with this problem, I cannot fully utilized all 4 memory slots on the MB which is a bummer.

Can anyone suggest a next step for me?

Thanks

[AsrockNewbie]

Re: 870 Extreme3 Dual Channel Memory Problem

Tried to downclock your memory to 1333MHz and force them to single channel?

[secured2k]

Re: 870 Extreme3 Dual Channel Memory Problem

I've built a few systems with this board and have never had this problem with the same OCZ memory. Dual channel mode requires identical memory chips in slots of the same color. When you put the chips in different color slots, the CPU's Memory controller will operate in Single Channel Mode. The difference is significant in memory intense operations.

I can only suggest that you verify the memory timings and voltage is set correctly when using the memory in dual channel mode.

OCZ Memory: 1.65 Volts, 8-8-8-24-2T @ 800MHz DDR3_1600
Corsair Memory: 1.65 Volts, 9-9-9-24-2T @ 800MHz DDR3_1600

If you install both, you will need to use the slowest speed (1.65v 9-9-9-24-2T).

Also, make sure in the BIOS you turn off "Away Mode Support" in the ACPI Settings.

If the problem still exists, it may be a problem with the CPU or motherboard.

*** Reference: Page 15 of the Manual (2.3 Installation of Memory Modules (DIMM))