GA-Z97MX-Gaming 5: Ram slots issue

[Unnatural]

Hello,
I'm building a pc for my brother with a Z97MX-Gaming 5 I bought few months ago (and used for some time with no big issues). Now I've found it can boot if there's a RAM stick on slot 2 and/or 4 (the two closest to the CPU socket). If I put RAM sticks only on slots 1 & 3, the PC starts normally.
I've already experienced a very similar problem with another motherboard, which has a knows issue caused by overthightened screws on case and CPU cooler, which warps the pcb, so it can be solved by adjusting their tension.
It is the same for the Z97MX? I've tried a couple times with no success, so I'd like to know if it's something else.
Thanks in advance!

[shadowsports]

Greetings,
Nothing on a motherboard, mounts, connected devices, peripherals, etc need to be torqued down.  Finger tight, maybe a snung more is plenty.  I doubt your issue has anything to do with mounting.  If you'd like assistance, please provide your full systems specs:

Board rev
BIOS version
CPU
Memory (brand, model)
Is the memory on the QVL for the board?
Is it matched?

Since it boots with two sticks, we don't need your PSU info.  Any other troubleshooting steps you've performed, etc.      

[Unnatural]

Hi, thanks for you reply.
My board is rev 1.0, and I was able (running 1 RAM) to flash the latest BIOS (F6) from the F4. I'm using a i5 4690k (which works fine on my other pc, and on this with a single module, anyway).
I tried HyperX 1866 RAM in any combination of 2 and 4 modules, and Corsair Dominator Platinum 2133 (Corsair's LED light up when in the "faulty" slots).
I reseated the CPU a couple times, making sure there was no dirt or bent pins.
Also I tried with and without a system disk and discrete GPU.
A lot of CMOS clear now and then.

[shadowsports]

Greetings,
Board handles up to 32GB or Ram.  For best results 2, 4 or 8GB modules should be used. They should be matched

Memory Support >Support for DDR3 3100(O.C.) / 3000(O.C.) / 2933(O.C.) / 2800(O.C.) / 2666(O.C.) / 2600(O.C.) / 2500(O.C.) / 2400(O.C.) / 2200(O.C.) / 2133(O.C.) / 2000(O.C.) / 1866(O.C.) / 1800(O.C.) / 1600 / 1333 MHz memory modules

Anything above 1333Mhz (SPD) or 1600Mhz (XMP1 Profile) will require over clocking for compatibility.  Have a look at M.I.T. section in BIOS.

[Unnatural]

Greetings,
Board handles up to 32GB or Ram.  For best results 2, 4 or 8GB modules should be used. They should be matched

Yeah, they are.

Anything above 1333Mhz (SPD) or 1600Mhz (XMP1 Profile) will require over clocking for compatibility.  Have a look at M.I.T. section in BIOS.

Well, this sounds strange, since I've always seen RAM speed downgrade in similar cases, and every other z97 mobo I owned worked with 1866 RAM at rated speed without OC. Also, the BIOS says the ram runs @1866 when running with slots 2&4 empty.

Guess I'll get something else and keep this mobo as an emergency replacement!

[shadowsports]

Your "k" CPU is unlocked.  Pushing things a little shouldn't be a big deal.  Your choice though 

[phantom_x]

Can we overclocking the DDR3 alone ,without the K series CPU (I mean using non-K series CPU) ?

Greetings,
Board handles up to 32GB or Ram.  For best results 2, 4 or 8GB modules should be used. They should be matched

Memory Support >Support for DDR3 3100(O.C.) / 3000(O.C.) / 2933(O.C.) / 2800(O.C.) / 2666(O.C.) / 2600(O.C.) / 2500(O.C.) / 2400(O.C.) / 2200(O.C.) / 2133(O.C.) / 2000(O.C.) / 1866(O.C.) / 1800(O.C.) / 1600 / 1333 MHz memory modules

Anything above 1333Mhz (SPD) or 1600Mhz (XMP1 Profile) will require over clocking for compatibility.  Have a look at M.I.T. section in BIOS.

[Unnatural]

Can we overclocking the DDR3 alone ,without the K series CPU (I mean using non-K series CPU) ?

Actually, Z97 boards (the top end ones, at least) usually do automatically run the RAM at the max rated frequency.
BTW, I just gave my Z97MX another chance with a kit of 1333 DDR3 from another PC, and same thing: pre-POST power loop with a module on 2 or 4, ok elsewere. Not bothering anymore with it, just getting a replacement =_=

[shadowsports]

Agree, small rash of recent posts Z97, Z170 threads where people are having POST issues when 4 slots are populated.  Makes you wonder. 

I did mention in another post that faster memory should and usually does work down clocked in a slower system, but am seeing less tolerance and compatibility of this with newer boards, BIOS, CPU combinations.  Could be related to the BIOS and the way frequency and timing is handled.  Pure speculation on my part and I'll be the fist to admit I'm new to Gigabyte boards.  Some of my friends who still use Asus are seeing similar behavior on many of their boards.  Doesn't seem to be any one manufacturer or thing all can pin down.  Based on this I tend to err on the side of caution.  Paying particular attention to QVL and sticking closely to what has worked well for me previously.  Nothing's worse than troubleshooting out of the box POST and detection failures after investing in shiny new hardware.