RAM compatible with motherboard?

[AngryPockets]

I have a new computer. Specs, for those curious:
-850w power supply
-ASUS B150 Pro Gaming Aura motherboard
-MSi GeForce GSX 970 graphics card (4G DDR5)
-i7-6700 quad core processor
-8 GB G-Skill DDR4 RAM

It worked great for awhile, but then it slowed to a crawl and eventually stopped working. I've ruled out the processor as the issue, and a fella on this site helped me narrow down the problem to the DRAM.

So I ordered some new RAM. I previously had a 4GB stick each in the 2nd and 4th DIMM slots (as per the manual's instructions). After it stopped working, I put the new sticks in the 1st and 3rd slots, and the machine booted right up.

So I put the old sticks back in the 2nd and 4th slots (so all 4 slots are used), and everything ran beautifully.

But then it slowed down again, and now it won't boot. The motherboard's boot diagnosing lights confirm the DRAM is the problem again.

RAM: http://www.newegg.com/Product/Product.aspx?Item=N82E16820231937

motherboard: http://www.newegg.com/Product/Product.aspx?Item=N82E16813132693

What's going on? Is the RAM not compatible with the board?

 

[timeconsumer]

You need to eliminate some variables. You had a ram problem, but you used the same ram and the same slots that were suspect with a new kit. Try the new ram in both slot positions 1+3 and 2+4. See if it's a problem with the slots. If both slot combinations run fine, then check the old ram kit. Try both sticks in 1+3 and then in 2+4, see how it runs. Try each stick individually.

Also consider that the ram you bought is DDR4-3000 1.35v. Did you enable XMP in the BIOS? If not, it is likely defaulting to DDR4-2133 1.2v. Now, a 3000 kit should be able to run undervolted at 2133 1.2v, but not necessarily. It may not be stable below 1.35v.

 

[Tradesman1]

The mobo doesn't support 3000 DRAM, your sticks if running at 2133 should prob be set to about 12-13-13-30 or so for 2133 and the BIOS may well have them at sloppy timings like 15-15-15 33 or whatever

 

[AngryPockets]

@timeconsumer
Okay, I did some experimentation with both my old and new RAM sticks. I used about every combination I could think of.
1) New Card in #1 and #2
Old Cards in #3 and #4 = no boot
2) New Cards in any 2 slots = didn't boot every time, runs a bit slow when it does
3) Old Cards in any slot = doesn't boots
4) I've been able to consistently boot into both BIOS and Windows with one of the new cards in slot #3.

@Tradesman1

From the BIOS, I can increase the voltage up to 1.8v (It's set to 1.2v, by default). CPU-Z program tells me the RAM is running at 1064.1 MHz (double for dual-channel puts it at about the 2133 MHz).

So the questions:
Is it safe to set it manually to 1.35v and 2133 MHz?
And is it necessary to change the voltage if I'm reducing the frequency?
Is it even necessary to reduce the frequency, since CPU-Z seems to indicate its running at 2133 anyway?

 

[Tradesman1]

What timings do they have the sticks at? If you leave the DRAM to defaults (2133) and just change the timings the voltage should be at 1.2. If any problems try them at 1.25 with the timings I provided