The motherboard reduces the voltage for RAM and affects its stability, isn't there?
The motherboard reduces the voltage for RAM and affects its stability, isn't there?
Hello,
I own DDR3 memory KHX1866C9D3/4GX with XMP profiles. When configured at 1.65V, HwInfo indicates the actual voltage is 1.61V. To achieve the desired 1.65V average, I adjusted it to 1.685. However, it can fluctuate down to 1.641V (or 1.637V).
My motherboard is an Asus P9X79 Pro, paired with an Xeon E5-2690v2 CPU. The RAM setup includes seven sticks. Ideally, everything would function without issues, but it currently triggers memory errors during standard XMP timings of 9-11-9-27 at 1866 MHz.
It seems the voltage reduction might be the cause. For instance, when resetting CMOS and selecting the default XMP profile, I wonder if errors would appear at the lower voltages or with the XMP settings. I lowered the timings to 9-11-9-28 and haven’t seen any errors for about an hour now. Still unclear what these numbers mean.
In the BIOS, there are numerous memory power control options like DRAM Current Capacity, DRAM Voltage Frequency, and DRAM Power Phase Control. Which settings should I choose? The manual isn’t very helpful. Options range from Optimized to Extreme, Efficiency to Performance. What does "Efficiency" really mean here? Is it optimized phase or full phase?
There are many auto options available, but I haven’t adjusted them. So I’m uncertain whether I need further clarification. Thanks for your attention.
The 7 DIMM setup isn't suitable for that board. I suggest using only 6 DIMMs, following the manual's advice and aiming to match DIMMs from the same kit in the right slots for their intended channel roles. For dual-channel boards, place two pairs—each pair in A2 and B2, or A1 and B1—and with mixed kits, this maximizes compatibility chances.
Choosing XMP doesn’t correctly configure all timings, except for the initial four. It incorrectly assigns timing values. I need to remember to recalibrate these settings each time I perform an action.
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
Optimization for Read to Write CMD Turn-around Time: none required
Optimization for Write to Read CMD Turn-around Time: none required
Optimization for Back 2 Back CMD Turn-around Time: none required
Optimization for System Command Rate Mode: Default
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. 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.
I damaged my DDR3 motherboard by using 1.65 volts memory for several years. I plan to lower it to 1600 and test 1.5-1.55 volts just in case.
And consider getting a full quad channel setup as suggested.
I'm tired of the Kit 3, and I took it out before reading the answer.
It's overheating; it's extremely hot.
I should test the kits 1 and 2, but overheating will still happen.
Thank you for your responses. I'll think about it.
Are all the kits identical in model number? Every DIMM shares the same part number? Yes, I’d test lowering the DRAM voltage to 1.641v and observe the temperature changes. When you refer to "hot," are you describing the actual temperature readings during heavy memory usage?