[SOLVED] ASUS TUF gaming Z490plus 64G DRAM instablility

[John.jin_1]

Hello,
I've bought ASUS TUF GAMING Z490-PLUS(WIFI) with G.SKILL Trident Z RGB (32GBX2) DDR4-4000.
I inserted both RAMs in DDR4_DIMM_A2 and DDR4_DIMM_B2 but it hanged my PC repetitively( in Bios I see DRAM bus was set to Auto and the motherboard set it 3600 in Auto mode).

Now, I've inserted both RAMs in DDR4_DIMM_A1 and DDR4_DIMM_B1 and everything works fine. However, In this mode DRAM frequency more than 2666Mhz makes my motherboard unstable(it shows me the instability in POST screen). when I set my DRAM frequency to 3600 or 4000 it shows me instability message and in bios mode I see it changed my DRAM to 2666Mhz to become stable.

I wonder why this mother board with this specification

4 x DIMM, Max. 128GB, DDR4 4800(O.C.)/4600(O.C)/4500(O.C)/4400(O.C)/4266(O.C.)/4133(O.C.)/4000(O.C.)/3866(O.C.)/3733(O.C.)/3600(O.C.)/3466(O.C.)/3400(O.C.)/3333(O.C.)/3200(O.C.)/3000(O.C.)/2933(O.C.)/2800(O.C.)/2666/2400/2133 MHz Non-ECC, Un-buffered Memory
Dual Channel Memory Architecture

works in this manner.

I will be grateful if you could help me to increase my DRAM frequency and make my PC stable.

 

[Aeacus]

I wonder why this mother board with this specification

4 x DIMM, Max. 128GB, DDR4 4800(O.C.)/4600(O.C)/4500(O.C)/4400(O.C)/4266(O.C.)/4133(O.C.)/4000(O.C.)/3866(O.C.)/3733(O.C.)/3600(O.C.)/3466(O.C.)/3400(O.C.)/3333(O.C.)/3200(O.C.)/3000(O.C.)/2933(O.C.)/2800(O.C.)/2666/2400/2133 MHz Non-ECC, Un-buffered Memory
Dual Channel Memory Architecture

works in this manner.

I guess you didn't look your MoBo memory QVL list beforehand.
Link: https://www.asus.com/Motherboards-C...F-GAMING-Z490-PLUS-WI-FI/HelpDesk_QVL_Memory/

As seen from there, it does support 4000 Mhz RAM, when all 4 slots are populated, IF the RAM is either: Crucial BLE8G4D40BEEAK.M8FE1, BLM8G40C18U4B.M8FE1, BLM8G40C18U4BL.M8FE1 or Thermaltake R009D408GX2-4000C19A, R016D408GX2-4000C19A.

Your G.Skill RAM isn't confirmed by Asus to work at 4000 Mhz when all 4 slots are populated. If you were to remove 2x RAM sticks, your MoBo should be able to run your RAM at 4000 Mhz since that's what is confirmed to work at, with G.Skill RAM.

Btw, the reason why all your 4 RAM sticks work at 2666 Mhz the most, is because that is JEDEC standard and it has to work at that speed.

At this point, you have 3 options:

1. Remove 2x RAM sticks, so the rest can work at 4000 Mhz.
2. Use all 4x RAM sticks, while keeping the speed at 2666 Mhz.
3. Buy the specific RAM, listed in memory QVL, that is guaranteed to work at 4000 Mhz when all 4x RAM slots are populated (you have a choice between 5 RAM sets, listed above).

 

[John.jin_1]

Dear Aeacus,
I really appreciative of your response.

Maybe I explained my problem badly. I have just 2 RAMs and these don't work properly in different types I inserted them in to my Motherboard. I don't have 4 RAMs.

 

[Aeacus]

Maybe I explained my problem badly.

Actually, the fault is at my part since somehow, i thought that you have a set of 4 RAMs, rather than a set of 2 RAMs.

I have just 2 RAMs and these don't work properly in different types I inserted them in to my Motherboard.

From the same link i linked above, according to Asus, the only 2x 32GB set that they tested (and most likely the only one they got working) above JEDEC speeds is Crucial CMK64GX4M2C3000C15 (Ver5.49) @ 3000 Mhz. All other RAM sets, that aren't listed there, have to work at 2666 Mhz, which your RAM does work.

At this point, there is little you can do. Your options are:

• Return the current RAM and buy the exact RAM listed in memory QVL, to get the speed Asus guarantees that you'll get. E.g G.Skill F4-3600C17Q-64GTZ (4x 16GB) @ 3600 Mhz, pcpp: https://pcpartpicker.com/product/4y...-4-x-16gb-ddr4-3600-memory-f4-3600c17q-64gtzr
• Keep the current RAM but be stuck with 2666 Mhz.
• Replace the MoBo. With this, you'll need to check new MoBo's memory QVL against your current RAM and if it does run at 4000 Mhz there or not.

MoBo specs, namely RAM speeds over JEDEC standard, are like cloak and dagger. While the MoBo does support RAM speeds up to 4800 Mhz, what MoBo makers doesn't tell you right away, is that there are specific and select few RAM modules, that work at those speeds with the given MoBo. Hence why there is memory QVL list. So, that people know what RAM to buy.

It's like when you'd be pairing CPU with MoBo. Just because e.g MSI Z170A Gaming M5 MoBo has LGA1151 CPU socket, doesn't mean that any LGA1151 CPU fits it. If i were to buy i5-9600K, which has LGA1151 socket, you can be sure that i can't pair it with MSI Z170A Gaming M5 MoBo.