GA 990FXA UD3 3.0 PROBLEM WITH 16GB RAM

[Urugamer]

HI, how are you? my name is Eduardo.

I have a gigabyte mother ga-990FXA ud3 version 3.0, have cpu fx 8320, and I bought 4 memories kignston hyperx 4gb 2400 mhz, the problem that I can not get my system to boot with 4 modules only run at 1333 mhz not achieve more speed than this. usually with 8gb ran to 2133 without any problem, any solution? Thank you.

[DarkstaR]

Hello Urugamer normally you won't meet any problem running your four memory sticks with your vishera but only at 1333mhz or 1600mhz... indeed those FX processors (4,6 or 8 cores) only accept 1866mhz or more with 2 sticks and not with four...this is a limitation of the memory controller (cpu-northbridge/uncore) 
For my case i'm running only 2 sticks (1600mhz labelled) but with bios tweaking i'm able to run them at 1866mhz and 2133mhz always with 1,50v stock voltage 

[Urugamer]

thank you very much for the reply-

[DarkstaR]

You're welcome !!! 

[MisterEd]

DDR3 Memory Frequency Guide
http://support.amd.com/us/kbarticles/Pages/ddr3memoryfrequencyguide.aspx

[DarkstaR]

Well i think this explanation is for reference only... here are my settings to see my 2 sticks of ram set at 1066/2133 instead of 800/1600 !