i got a 5960x in the x99 ftw-k mobo i got from a friend.  i've got 2133 ram in there running at 2667hz but im curious why my bios has no 2800 or 3000 option, it has a 3200 mhz option so im wondering if it's possible to buy 3200 mhz ram to get that speed running.  need a gpu upgrade but wanted to make sure there wasn't performance left on the table for when i do.  I hear the memory controller on these boards can't sustain 3200 mhz.  hoping that's not true.  

3200 should work ... it Keeps the  BCLK @ 100 ...... BCLK @ 125 may issues
 
VSA Voltage Offset may need to be increased to run high speed memory.
 
as mentioned by Sajin ... the IMC in the CPU matters

Cool GTX
3200 should work ... it Keeps the  BCLK @ 100 ...... BCLK @ 125 may issues
 

 
as mentioned by Sajin ... the IMC in the CPU matters

yeah i try to not increase the base clock of the mobo.  its an older mobo i got from my friend and it used to glitch out on us sometimes but has been pretty reliable lately. a couple times i had to remove the first ram stick and reinsert to get the board to post.  
so 3200 mhz ram isn't cheap, but i think i can score some 3000 mhz ram on ebay for a steal, even if there's no 3000 option on my mobo bios, if i put in 4 matching 8gb sticks of 3200 mhz ram and i enable xmp, they should run at 3000 mhz then right?  

3000MHz = BCLK of 125 MHz  (if I remember correctly) .... & that is not good
 
 

Just two questions according to RAM speed and possible effects.
 
I run the X99-FTW-K with BIOS 2.08. Had 4x16 GB corsair vengeance LPX 3000 MHz CL15 running (using XMP Profile). Because they were not available at the
market the moment I wanted to upgrade I additionaly bought 4x16 GB corsair LPX 3333 MHz CL16. My thought was that they operate together at the lower 3000 MHz CL15. 
 
No success. XMP did not sort it out. After hours of reading and trying possible configuration parameter combinations I ended up with 2800 Mhz and CL14. It is running rock solid - i7-6850k CPU permanently overclocking to 4.2 Ghz stable.
 
My questions would be.
1. Am I missing much with my current timings in relation to the 3000 MHz CL15
2. I have an offer to buy another 4x16 GB Kit of the same 3333 MHz CL16 LPX RAM. How likely is it the system will run all 8 sticks with 3333 MHz CL16 (and not staying with 2800 CL14) and - if they run that speed - is there a chance for a signifikant benefit in CPU / RAM intensive work in comparison to the 2800 CL 14?
 
Please let me know what you think.
 
Thank you

Dear rjohnson11,
 
thanks for your replay.
Maybe I was not precise enough in my further description.
My goal is to run 128 GB RAM (8x16 GB) in the highest possible configuration. 3000 Mhz would be fine because of the X99 sweetspot 
 
I did indeed buy another corsair vengeance 4x16GB 3333CL16. But again - no success. Let me short explain what is working and what is not working.
 
* 4 x 16 GB 3333CL16 -> shown XMP 3200 16-18-18-36 -> xmp seleceted -> working fine 
 
* 8 x 16 GB 3333CL16 -> shown XMP 3200 16-18-18-36 -> xmp seleceted -> not working fine -> restart after saving BIOS not working -> infinite restarts / retrying to boot -> mainboard showing CODE 69 -> cold start climbing over that hill after a cold restart, but still some automaticv board restarts-> booting in W10 is working -> AIDA64 performance test crashes -> BSOD.
 
* 8 x 16 GB 3333CL16 -> shown XMP 3200 16-18-18-36 -> manual seleceted 3000 15-17-17-35 -> one step further down -> not working fine -> change: no problem  any longer with the board boot sequence showing CODE 69 -> but BSOD while booting win 10.
 
* 8 x 16 GB 3333CL16 -> shown XMP 3200 16-18-18-36 -> manual seleceted 2800 14-16-16-33 -> way below RAM specs -> working fine -> 
 
I decided to put in my older  RAM configuration
* 4 x 16 GB 3333CL16 + 4 x 16 GB 3000 C15 -> shown XMP 3000 15-17-17-35 -> xmp seleceted -> not working fine -> BSOD while booting win 10
 
* 4 x 16 GB 3333CL16 + 4 x 16 GB 3000 C15 -> shown XMP 3000 15-17-17-35 -> manual seleceted 2933 15-17-17-35 -> maybe working fine -> only took some AIDA64 benchmarks with success
 
because of better latency I switched back to:
* 4 x 16 GB 3333CL16 + 4 x 16 GB 3000 C15 -> shown XMP 3000 15-17-17-35 -> manual seleceted 2800 14-16-16-33 -> working fine -> as for many months now.
 
All errors are repeatable. So I assume it has something to do with the IMC of my i7-6850k when managing 8 RAM sticks (no errors with 4 sticks).
What would be your opinion to that picture I described above? 
I am just curious to understand what causes this behaviour
 
Thank you.