Weird RAM Timings

[sphinx64]

I have 4 sticks of Corsair Vengeance LED CMU16GX4M2C3200C16 with a total of 32Gb RAM
RAM is now runnıng at 2880MHz (confirmed with AIDA, CPUz, Bios, etc.) with Bios settings (9945);
DOCP set to 4
BCLK Frequency=120.000
Memory rating set to 2880MHz (actually there was this option instead of 2933)
Core Performance Boost=enabled
CPU Core Voltage=auto
CPU SOC Voltage=manual
- VDDSOC Voltage Override=1.1
DRAM Voltage=1.35
DRAM Boot Voltage=1.35
DRAM CL=16
DRAM RCD=18
DRAM RP=18
DRAM RAS=36
DRAM RC-RFC1-RFC2-RFC4-RRDL-RRDS-FAW=all auto (manual entry causes instability - all of the values obtained by AIDA and Thaiphoon Burner)
ProcODT_SM=68.6
Cmd2T=auto (either 1T or 2T causes instability)
Gear Down Mode=auto
Power Down Enable=auto
CLDO_VDDP=auto (no matter how hard I tried to follow Elmor's instructions properly, it wouldn't stick)
Rest of the Bios values are at default.
Memory passes all the tests and sytem is stable, however I am a bit nervous of the 2880MHz, as I never heard of such a weird #. Any ideas or suggestions?

[entropic-remnan]

My opinion is D.O.C.P. stands for "Doesn't Operate Computer Properly". I have very similar Corsair RAM that I think is using the same chips and it runs at 3200 on 9945. Bclk is 100 and the 3200 strap is selected. I hate that D.O.C.P. setup.

I can't imagine what is causing your problems unless it's that D.O.C.P. overclock. Try using the method in my post on the Corsair Dominator CMD... memory. Looking at what you've posted we are using probably the same Samsung E or D-die.


By all means set 2T and turn Gear Down to Disabled. No good can come of gear down with these chips I don't think. 2T is safer for testing and you can try 1T later but it won't work for me.

[sphinx64]

entropic-remnants wrote:
My opinion is D.O.C.P. stands for "Doesn't Operate Computer Properly". I have very similar Corsair RAM that I think is using the same chips and it runs at 3200 on 9945. Bclk is 100 and the 3200 strap is selected. I hate that D.O.C.P. setup.

I can't imagine what is causing your problems unless it's that D.O.C.P. overclock. Try using the method in my post on the Corsair Dominator CMD... memory. Looking at what you've posted we are using probably the same Samsung E or D-die.


By all means set 2T and turn Gear Down to Disabled. No good can come of gear down with these chips I don't think. 2T is safer for testing and you can try 1T later but it won't work for me.

Without DOCP setting, the RAM only works at 2133; every possible setting and combination already been tried....
I also tried it with setting it to 2T, but no avail...
When setting to auto, CPUz tells me that it runs at 2T
Weird again and Gear Down disabled at any combination caused instability.

[entropic-remnan]

DOH! I just saw you had 4 sticks. This system has issues with 2 dimms on each channel and often won't go past 2666 to 2933. I'm only running 16 gb.

May I suggest you run just two as a test in the A2/B2 slots and see what you can achieve? That will allow you to verify your RAM and then you can proceed to find out how to get the most out of 2 DIMMS per channel.

[sphinx64]

entropic-remnants wrote:
DOH! I just saw you had 4 sticks. This system has issues with 2 dimms on each channel and often won't go past 2666 to 2933. I'm only running 16 gb.

May I suggest you run just two as a test in the A2/B2 slots and see what you can achieve? That will allow you to verify your RAM and then you can proceed to find out how to get the most out of 2 DIMMS per channel.

I also tried with different sticks @A2/B2 slots with no avail. The most I got was 2666 with 2 sticks... (again with every possible combination available in Bios). This weird 2880 is the highest I could get with 4 sticks; however, I am a bit uneasy of the weird #, as I am not sure it will cause any problems in the long run...

Thanks for the advice(s).

Regards.

[entropic-remnan]

Well, the number is whatever you can get. You aren't hurting anything.

I accept your explanation about trying everything, but from my personal experience I find I've often confused myself about the combinations or conditions. Since I don't have anything else technical to suggest, my only advice would be to take a step back, start over, and see if maybe you missed anything. That approach often results in me slapping myself in the head as I realize where I went wrong. You're not me, lol, so possibly it's of no use but at this point it's all I can suggest.

So, to review what I'd do starting with 2 sticks in A2/B2:

• Clear all the memory overclocking settings, get out of D.O.C.P. and set to manual.
  
• Set a 100 mhz Bclk.
  
• Select a 3200 strapping.
  
• Enter ALL the timings you have manually, 2T, Gear Down disabled. Some in that huge list will be in Auto obviously.
  
• Use your SOC/SB/RAM voltages to taste. I'm using 1.4 for my RAM.
  
• Set ProcODT to what works. It's 80 for me.
  
• Manually set the VTTTDDR voltage to 1/2 memory voltage. I mention that in my post on getting mine up to speed.
  

[sphinx64]

entropic-remnants wrote:
Well, the number is whatever you can get. You aren't hurting anything.

I accept your explanation about trying everything, but from my personal experience I find I've often confused myself about the combinations or conditions. Since I don't have anything else technical to suggest, my only advice would be to take a step back, start over, and see if maybe you missed anything. That approach often results in me slapping myself in the head as I realize where I went wrong. You're not me, lol, so possibly it's of no use but at this point it's all I can suggest.

So, to review what I'd do starting with 2 sticks in A2/B2:

• Clear all the memory overclocking settings, get out of D.O.C.P. and set to manual.
  
• Set a 100 mhz Bclk.
  
• Select a 3200 strapping.
  
• Enter ALL the timings you have manually, 2T, Gear Down disabled. Some in that huge list will be in Auto obviously.
  
• Use your SOC/SB/RAM voltages to taste. I'm using 1.4 for my RAM.
  
• Set ProcODT to what works. It's 80 for me.
  
• Manually set the VTTTDDR voltage to 1/2 memory voltage. I mention that in my post on getting mine up to speed.
  

Will do all over again per your advice (although I spent hours or even days of different combinations, including yours). I also set the VTTTDDR voltage to 1/2 memory voltage already...
Already tried the ProcODT 80 with no avail. 68.6 works for me.
Will let you know.

Again I appreciate your help.

Regards.

[entropic-remnan]

Well, I may not be helping. Good luck and I hope you find a solution. One other thing I remember but didn't mention is to make sure spread spectrum is off. It causes clock modulation and some say it hoses memory timing, not sure.

Did you buy those as two 16 gb kits? I've never experienced this but on overclock.net somebody was saying to guy 32gb as a single kit because the kit's chips are all "matched". I have no idea if this is true or not. Seems like it wouldn't make enough difference if they have the same timings, but DDR4 is like voodoo witch-doctor stuff.

[sphinx64]

entropic-remnants wrote:
Well, I may not be helping. Good luck and I hope you find a solution. One other thing I remember but didn't mention is to make sure spread spectrum is off. It causes clock modulation and some say it hoses memory timing, not sure.

Did you buy those as two 16 gb kits? I've never experienced this but on overclock.net somebody was saying to guy 32gb as a single kit because the kit's chips are all "matched". I have no idea if this is true or not. Seems like it wouldn't make enough difference if they have the same timings, but DDR4 is like voodoo witch-doctor stuff.

😄 Yes it is in a way voodoo stuff. I checked each and every stick with Thaiphoon Burner for SPD and timings. After years of building computers, each stick was verified independently that they were working fine and pristine before going into actual build. I did not know about the spread spectrum. After 34 years of building, you always get to learn something new, and that's what I love about computers. I am not sure where in the heck it is located in the bios but will find it and try it for sure.

Thanks.

[Praz]

Hello

The preset memory divider speeds are based on a 100MHz BCLK speed. Changing the BCLK speed will also alter the memory speed for a given divider. That 2933MHz is no longer an option with the BCLK speed set to 120Mhz should be expected. Memory is spec'd to run as sold. When combining kits one should plan on manual tuning and/or reduced speed or timings. The Spread Spectrum setting is for the switching frequency of the VRM circuit. Its chosen setting will have no influence on BCLK frequency but for other reasons is best set to disabled when overclocking.