Question Motherboard lowers the RAM voltage and RAM stability, and that's all ?

[terrans]

Hello,
I have DDR3 memory KHX1866C9D3/4GX with XMP profiles. When it's set to 1.65V, the real voltage, according to HwInfo, is 1.61 V.

To reach the 1.65V average, I set it to 1.685. But it can drop to 1.641 V (or 1.637).

Motherboard: Asus P9X79 Pro
CPU: Xeon E5-2690v2
RAM: KHX1866C9D3/4GX x7 🙄 7 sticks of RAM.

Everything would be fine if it worked without errors. But it gives memory errors on standard XMP timings 9-11-9-27 at 1866 mhz

Probably, I could forget that it actually lowers the voltage. For example, when reset CMOS, and select "default" XMP profile. Should I expect that it would give errors on "standard" (actually dropped) voltage and "standard" (XMP) timings.

I lowered the timings to 9-11-9-28, and it hasn't given me an error for about 1.5 hours now. I don't know the meaning of these digits 😳 I only know that the first is the "CAS Latency", and the others are "don't touch it while it works".

In the BIOS, there are many options for memory power control, such as "DRAM Current Capacity", "DRAM Voltage Frequency", and "DRAM Power Phase Control". But what should I select? The manual is not extremely useful. Optimized or Extreme. Efficiency or Performance. What the (hell) is the Efficiency is? Optimized phase. Full phase. Optimized to what?

There are a lot of options that are on Auto, but I didn't touch them.

So I don't know if I need an answer. Thank you for reading this 🤔

 

[Darkbreeze]

A 7 DIMM configuration is not a recommended memory configuration for that board. I would recommend you populate with only 6 DIMMs, based on the recommendation from the manual AND if possible that you try to use DIMMs that came together in the same kit in the correct slots for intended channel operation. For example, if this was a dual channel board I'd recommend that with two sets of two dimms you put two that came together in A2 and B2 and two that came together in A1 and B1. When using mixed kits this gives you the best chance of them playing nice together.

Did all of these DIMMs come in a single kit or is your memory configuration a mishmash of mixed kits?

 

[terrans]

It is in three kits.
Kit 1 is in A1, B1, D1.
Kit 2 is in A2, D2.
Kit 3 is in B2, C1.
Kit3 in B2, C2 wasn't working. Maybe faulty slot.

PS. 1 Error received after three hours.

 

[terrans]

Selecting XMP doesn't set correct timings, except the first four.

It sets wrong timings. I must not forget to adjust these timings every time when I do *something*.

Spoiler

Enthusiast / Certified Profile [Enabled]
Module VDD Voltage Level: 1.65 V
Memory Controller Voltage Level: 1.30 V
CAS# Latencies Supported: 7, 8, 9
Minimum SDRAM Cycle Time (tCKmin): 1.071 ns (933.3 MHz)
Minimum CAS Latency Time (tAAmin): 9.643 ns
Minimum RAS# to CAS# Delay Time (tRCDmin): 11.786 ns
Minimum Row Precharge Delay Time (tRPmin): 9.643 ns
Minimum Active to Precharge Delay Time (tRASmin): 28.929 ns
Minimum CAS Write Latency Time (tCWLmin): 10.000 ns
Minimum Write Recovery Time (tWRmin): 15.000 ns
Minimum Active to Active/Refresh Delay Time (tRCmin): 45.000 ns
Maximum tREFI Time (Average Periodic Refresh Interval): 7.786 us
Minimum Refresh Recovery Delay Time (tRFCmin): 160.071 ns
Minimum Internal Read to Precharge Command Delay Time (tRTPmin): 7.500 ns
Minimum Row Active to Row Active Delay Time (tRRDmin): 7.500 ns
Minimum Four Activate Window Delay Time (tFAWmin): 30.0 ns
Minimum Internal Write to Read Command Delay Time (tWTRmin): 7.500 ns
Supported Module Timing at 933.3 MHz: 9-11-9-27
Supported Module Timing at 800.0 MHz: 8-10-8-24
Supported Module Timing at 666.7 MHz: 7-8-7-20
Read to Write CMD Turn-around Time Optimization: No adjustment
Write to Read CMD Turn-around Time Optimization: No adjustment
Back 2 Back CMD Turn-around Time Optimization: No adjustment
System Command Rate Mode: Default

I haven't set three of them - tREFI (it's not "minimum" but "maximum"), and, and, and... the others are probably the same.

 

[Darkbreeze]

Please read the second section of my memory guide titled "Mixed memory (Or the odd man out)

How To - Troubleshooting problems with PC memory (RAM) and XMP profile configurations

In the beginning, there was......BIOS Before you go ANY further, go to the manufacturer product page for your specific motherboard model AND revision. Revision is an important aspect because for any given motherboard there may be more than one version of that model which will be identified...

forums.tomshardware.com

Even on dual channel memory boards mixing memory is quite often problematic in one way or another. On 4, 6 and 8 channel boards, it's MUCH more critical that all of the memory be matched and tested, coming in one package together from the factory. That is the only way there is every any kind of guarantee that they should work together, so long as they are compatible with the board in question and by compatible I don't just mean "the right TYPE of memory". I mean, compatible MODEL because not all memory that is the right type will work with every board which is WHY there are motherboard QVL lists and why the major memory manufacturers provide their own, even more discerning, compatibility lists.

If the memory is mixed, there are no guarantees you will ever get it to work together properly. AND, it's even MORE likely you won't when trying to get it to all work at the XMP, AMP, A-XMP or EXPO profile speed. That doesn't mean it can't, but as you've already seen, it doesn't mean it will either.

My recommendation would be that you consider selling all the memory you have now and buying ONE single kit that comes with all the capacity you require, that has been matched and tested from the factory. Otherwise, you will likely have to settle for reduced speed or timing configurations, or fewer DIMMs.

 

[Eximo]

I burned out my DDR3 motherboard running 1.65 volt memory for a few years. I would back it down to 1600 and run 1.5-1.55 volts just to be safe.

And get a proper quad channel kit as mentioned.

 

[terrans]

I am tired of the Kit 3, and removed it before I read the answer.
It's overheating. It's VERY hot.
I should test the kit 1 and 2, but the overheating will still occur.

Thank you for responses. I will think about it