Fatal1ty 990FX Killer/3.1 + 2400Mhz RAM

 

Before we continue with troubleshooting, you really should consider whether you want to go on with these memory sticks and achive 2400 MHz as more than 1866 doesn't add much to performance on the AM3+ platform. In fact, by raising from 2133 to 2400 MHz it does not perform any better and might causes further problems as you have to overclock CPU-NB from 2200 to 2400 MHz as well. CPU-NB speed has to be equal or higher than memory speed. It is possible that your CPU-NB causes the instability, not the memory itself.

 

I highly recommend striving for 2133 and leave the CPU-NB alone. The voltage needed to get above 2200 MHz is not worth the risk and might cause more trouble, even if you think it is stable!

 

You said that you had to set the XMP profile AND memory speed to 2400. What is the memory speed setting if you just set XMP? It could be that you can choose more than one profile (1866, 2133, 2400). If so, try the lower profiles.

If no profile works for you, it would be best to read out its timings for 1866 and/or 2133 MHz by using tools like CPU-Z (not showing all profiles), AIDA64 (hopefully the demo version is capable of showing it) or spec sheets from the manufacturer and set up BIOS manually.

 

To begin from the start, I recommend: Power off, clear CMOS and power on again. Now it should detect your CPU, memory, etc. as it was brand new. Once I switched two brands of modules between mainboards and switched back. After that one combo was unstable although set up exactly as before. I had to clear CMOS to get rid of whatever background settings...

 

After that try if you can boot and if that works try my recommendations.

 

Good luck!

 

You are right of corse that every memory controller has its limitations. But usually it works very well with higher frequencies (except >2200 MHz because of CPU-NB OC).

I am convinced however that not the controller is the prime limiter, but BIOS/EFI incompatibilities! Why else would one module work on one board and not on the other, but with the same CPU and its integrated memory controller? And BIOS/EFI Updates often state "enhanced memory compatibility".