Question Mismatched sub clock frequencies - Best Performance Setting

Sep 23, 2020
My motherboard is a Gigabyte 990FXA-UD3 V4.0 with four RAM slots. All four RAM memory cards are operating giving me 32gb of RAM. Two of the RAM cards are G.Skill RipJaws 10-11-10-30, 1.5 V 1866MHz, the other two are Corsair Vengence 9-10-9-27 1.5V, 1866Mhz.
The program "CPU-Z" shows CPU = Gigabyte AMD FX-6300 six-core processor, socket AM3+ (942). The memory pane in CPU-Z shows DDR3, channels = dual, size =32gb, DRAM frequency 669.6MHz, FSB:DRAM 3:10, CAS Latency = 9.0 clocks, RAS# to CAS delay = 9 clocks, RAS# precharge = 9 clocks, Cycle time 24 clocks, Bank Cycle time - 33 clocks. The SPD panel on CPU-Z shows slot 1 max bandwidth = PC3-10700 (667MHz) G.Skill and frequency jedec#5 = 666Mhz, jedec#6=666MHz, xmp-1866 = 933Mhz and xmp-1866 = 933MHz. Slot 2 is the same as 1. Slot 3 shows Corsair jedec #2 frequency = 457MHz, jedec#3 = 609MHz, jedec #4 = 666Mhz and xmp-932MHz. Slot 4 is the same as 3.

What I'm trying to achieve is having all four operating at their best speed even though their sub-clock frequencies are not the same. I went into my BIOS and tried to use the XMP settings on profile 1. This did not work and I had a failed boot so I selected to reset all setting to optimum. This is where I am now. I know just enough of this to get myself into trouble without some further advice and directions.


Mixing RAM kits is not recommended. Your memory is running at only 1340MHz due to mixing RAM kits. You really should purchase a 4 stick kit of 4x8GB to run 32GBs in your system. Do you regularly use 16GBs or more of RAM? Only then would putting 32GBs in make sense.

Is your current 32GBs fully stable? Did you boot off a Memtest86 USB and verify?
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