My DDR3 1333MHz shows up as... 400MHz

[Shockeru]

I'm using 3x2GB Corsair DDR3 1333MHz CL9 XMS3 + 3x4GB Kingston ValueRAM 4GB DDR3 1333MHz CL9 on my Gigabyte GA-X58A-UD3R. Unfortunately I don't have physical access to the server for a week or so, but I did a

dmidecode --type 17

on my Ubuntu 10.04 and got:

# dmidecode 2.9
SMBIOS 2.4 present.

Handle 0x0017, DMI type 17, 27 bytes
	Size: 4096 MB
	Bank Locator: Bank0/1
	Speed: 400 MHz (2.5 ns)
Handle 0x0018, DMI type 17, 27 bytes
	Size: 2048 MB
	Bank Locator: Bank2/3
	Speed: 400 MHz (2.5 ns)
Handle 0x0019, DMI type 17, 27 bytes
	Size: 4096 MB
	Bank Locator: Bank4/5
	Speed: 400 MHz (2.5 ns)
Handle 0x001A, DMI type 17, 27 bytes
	Size: 2048 MB
	Bank Locator: Bank6/7
	Speed: 400 MHz (2.5 ns)
Handle 0x001B, DMI type 17, 27 bytes
	Size: 4096 MB
	Bank Locator: Bank8/9
	Speed: 400 MHz (2.5 ns)
Handle 0x001C, DMI type 17, 27 bytes
	Size: 2048 MB
	Bank Locator: Bank10/11
	Speed: 400 MHz (2.5 ns)

(I removed unnecessary info)

Why 400MHz?

 

[sub.mesa]

Strange since if it would display the actual frequency i would expected 166MHz.

166MHz real clock * 8 (DDR3) = 1333MHz effective clock

As i understand.

 

[n7]

It's running @ DDR3-800 speeds; that's why

If you're @ stock; it's presently running @ the 6x multiplier.
8x = DDR3-1066
10x = DDR3-1333

 

[Shockeru]

n7, what does that mean exactly? What should/can I do?

 

[n7]

That means you didn't set the memory multiplier in the BIOS.
It is running at a lower one than you are expecting it to.

Note that the "official" supported speed is DDR3-1066, not DDR3-1333, so instability could occur in some cases without more tweaking/voltage if you set it to DDR3-1333.

You have to enter the BIOS & manually apply the higher speed; i'd then test with Memtest86+/HCI Memtest/LinX to ensure it is stable.