z390 phantom gaming 4 RAM question
Printed From: ASRock.com
Category: Technical Support
Forum Name: Intel Motherboards
Forum Description: Question about ASRock Intel Motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=113555
Printed Date: 17 Sep 2026 at 7:19pm
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com
Topic: z390 phantom gaming 4 RAM question
Posted By: Jvpix.com
Subject: z390 phantom gaming 4 RAM question
Date Posted: 24 Jul 2026 at 10:35pm
| Hi, I have the z390 phantom gaming 4 motherboard. I got 4 DDR4 memory modules, each one is 16gb, 2666v. they are not necessarily all the same manufacturer. when I put them all in the motherboard, the PC wouldn't boot up. Is this the reason why? thanks |
Replies:
Posted By: Xaltar
Date Posted: 24 Jul 2026 at 10:44pm
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Try each stick individually in slot A2 and make sure they are all working. If they all work fine then populate slots A2 and B2 and try with that using different combinations. If all the modules work in dual channel like that then populate all the slots and try. Mixing and matching RAM brands and models can cause issues, particularly when 4 modules are in use. More RAM modules = more chance of incompatibility. If you are using 2 kits of 2 then try them in different combinations, that can make a difference and may allow you to POST. Failing that, go into the BIOS with a single stick installed and set the RAM speed manually to 2133 and then try all 4 modules again. If that doesn't work you may be out of luck. Good luck  ------------- 
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Posted By: Jvpix.com
Date Posted: 24 Jul 2026 at 10:57pm
when the memory wasn't working, I didn't even get the option to press F2 for the bios. even when I put the original memory back in, the machine would boot to windows, but i never got the prompt to press F2 to get into the bios. |
Xaltar wrote:Posted By: Xaltar
Date Posted: 24 Jul 2026 at 11:24pm
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Try clearing CMOS. That should get you back to system defaults and sort out the issue with entering the BIOS. As a general rule, always clear CMOS before adding new RAM, it will force the system to retrain the RAM and might make your 4 modules work. -------------
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Posted By: Jvpix.com
Date Posted: 24 Jul 2026 at 11:28pm
| ok thanks |
Posted By: Jvpix.com
Date Posted: 24 Jul 2026 at 11:52pm
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I read this in the manual: "It is unable to activate Dual Channel Memory Technology with only one or three memory module installed". does that mean one or three memory modules installed wont' work at all or it will work but just not in dual channel mode? |
Posted By: Xaltar
Date Posted: 25 Jul 2026 at 2:00am
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One or 3 work in single channel mode but still work. -------------
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Posted By: Jvpix.com
Date Posted: 25 Jul 2026 at 3:58am
| I just noticed this thread is in the AMD motherboards. I have an intel cpu in this motherboard. but i'm sure all the info you gave me still applies right? |
Posted By: Xaltar
Date Posted: 25 Jul 2026 at 4:34am
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My mistake with the thread location but yes, the info is identical across platforms. Moved to the appropriate section. -------------
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Posted By: Jvpix.com
Date Posted: 25 Jul 2026 at 11:08pm
| why is it that ever since I tried getting these 16gb memory modules working in my machine, now when I turn on my machine, the screen is totally blank until it gets to the windows 11 login screen? I never get the prompt to press F2 for the bios. |
Posted By: Xaltar
Date Posted: 25 Jul 2026 at 11:40pm
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Did you move the display cable to a different output? That usually means the system didn't detect the monitor where it expected it during POST (Power On Self Tests). Try connecting your display to different outputs when you power on and see if it displays the POST menu then (F2 to enter BIOS plus the ASRock splash screen). The operating system will detect the display even if it isn't connected where the BIOS expects it. If you didn't move the display cable then I don't know what could have caused it, the BIOS being reset possibly. Did you manage to get all the RAM working together? -------------
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Posted By: Jvpix.com
Date Posted: 25 Jul 2026 at 11:42pm
| ok I put each of the new 16gb 2666v memory in the A2 slot and the machine would never boot. I then put a module in the A2 and B2 slot, still not bootup. I put in the original 16gb 2400v memory in the A2 slot and the machine boots up. I find it hard to believe all 4 of the 2666v memory modules are bad. I went into the bios and in the OC Tweaker section and noticed the DRAM Frequency was set to "DDR4-2133 (1:16) Auto". should I change it to "DDR4-2166" and try the 2666v memory again? |
Posted By: Jvpix.com
Date Posted: 26 Jul 2026 at 12:01am
| ok I put that setting to 2666v and it made no difference. so I put all my original memory back in. by the way, my original memory is all 2400v, but one module is 16gb and the other three are 8gb. could that configuration have made some kind of change in the bios that is preventing the 2666v modules to work? |
Posted By: Xaltar
Date Posted: 26 Jul 2026 at 12:17am
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It sounds like your 16gb module/s are not supported on your board. RAM compatibility can be a problem. Please list the brand and model numbers for each of your RAM modules. I thought based on your posts that you were using 4 8gb modules from different brands or models. Now you are saying you are mixing capacities too. That can be very problematic when using 4 modules together. See if the 3 8gb modules work together (just with the 3 modules). Your 16gb module might be incompatible with your system (made for AMD boards possibly). -------------
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Posted By: Jvpix.com
Date Posted: 26 Jul 2026 at 12:31am
| no the memory that is working is 16, 8, 8 and 8. they are all currently working. I put the 16 in the A2 slot. the ones that don't work are all 16gb, 2666v. so you're saying memory made for an AMD machine is different than that of an intel machine? |
Posted By: Xaltar
Date Posted: 26 Jul 2026 at 2:33am
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The memory itself is the same but it is tuned differently for the different platforms. This can lead to incompatibility. Sadly, not all RAM is compatible with all the motherboards it can fit into. This has been a major issue since DDR3 and only gotten worse since. If you have another DDR4 system to try it in I would do so. If not, I would return it for a refund. -------------
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Posted By: Jvpix.com
Date Posted: 28 Jul 2026 at 2:56am
| Hi Xaltar, I found out that the memory is ECC memory. it came from a spare machine that wasn't being used anymore. Sorry to have wasted your time. |
Posted By: Xaltar
Date Posted: 28 Jul 2026 at 3:05am
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Ah, yeah, that explains it. No problem at all, time spent trying to help someone is never a waste -------------
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