ndAsrock 970 PRO3 R2.0 a Crucial Dimms not working

Hellol at Asrockforum

I have the following Asrock 970 PRO3 R2.0 motherboard with a AMD FX8350cpu
and wanted to  update the current memory I had 8gb with each slot having 2gb in

I read the Tech specs and see that the motherboard supported upto 64gb
to I thought I would by the following memory

Crucial 16GB Kit (8GBx2) DDR3L 1866 MT/s (PC3L-14900) UDIMM 240-Pin

So I bought 2 kits so that I could add them to the 4 slots giving me 32gb of memory

However on installing the memory in the 4 slots i just get a black screen of bootup
if I remove the two middle memory chips the computer will bootup without problems

I can however add 2 of my old Memory chips in the middle slots giving me a total of 20gb

I thought that the other memory chips were faulty, but I have swooped them out
and they will only work in the 2 outer slots.

is there anyway I can add the Crucial memory to the middle slots?

Thanks for any advice in advance

Increase the DRAM voltage to 1.50V, Piledriver doesn't pair well with DDR3L (1.35V DDR3 memory) and this is much more true when you populate all 4 slots, so enter UEFI with only 2 sticks set memory to 1600MHz as said above, but set memory voltage to 1.50V also if still no boot with 4 sticks, increase memory voltage to 1.55V and report back

Edited by cristy6100 - 21 Apr 2018 at 9:19pm

If you want you can try to set 1866MHz now and see if it works, it should, because FX 8350 can work with 2133-2400MHz memory with 2 slots, it should do 1866MHz with all 4 slots populated.

Edited by cristy6100 - 21 Apr 2018 at 11:07pm

So its not working with all 4 dimms populated if you set 1866MHz and 1.55V?

Edited by cristy6100 - 22 Apr 2018 at 5:06am

Glad this was sorted. A few notes as a reminder:

-If you intend to populate or four slots, you should always buy a four module kit instead of two kits with two modules. Separate kits are not guaranteed to work together, not even if it's the same memory. I would also assume that if two different kits do work together, they may not be as easy to overclock as one single kit. This is difficult to confirm, however, since overclocking potential always depends on the kit itself. I'm not sure if anyone has ever done any statistical comparison of these two cases.

-The maximum stock RAM speed for FX-processors is 1866 MHz only when the motherboard has two memory slots and they are both populated. If there are four memory slots of which two are populated, the maximum stock speed is 1600 MHz. The same is true if all four memory slots are populated with single rank memory. However, if all four slots are populated with dual rank memory or a mix of single and dual rank memory, the maximum stock RAM speed is 1333 MHz. Reaching speeds higher than these are of course possible, but it's not guaranteed.

So, two rule of tumbs for future reference:

1. Always buy a single RAM kit, if possible.
2. Always go for two modules instead of four, if possible.