Asus Z390-F not running 64GB of Corsair

[RayVM]

Have been running 2x16GB Corsair Vengeance Pro on my Asus Z390-F with no problems for the last 5 months, been a great build so far. But with current work loads I've bought another of the same RAM. Problem is, I can only get 3 sticks to run - 48GB, doesn't matter which order they're in in terms of slots, it sees them no problem. When they all didn't run first time, I tried one at a time, when through the whole test and got up to 3 sticks working in either slots. Any ideas what could be preventing all 4 from working? Fairly sure I've ruled out a faulty slot or stick of RAM. Even tinkered with the MemOK switch, no luck either way.

 

[wookiee87]

it sounds like a memory slot problem or your cpu has got a iffy imc (internal memory controller), have you looked at all the ram slots and checked any kind of debris or perhaps dust build up inside, if so carefully clear the slots and try again, if only 3 stick show up try each kit of ram separately in dual channel mode, if all the ram works as should then I'd say your cpu is the problem, don't forget mainstream socket chips only support dual channel ram officially (both amd and intel)

failing that you could try updating your bios as earlier versions are iffy with ram, normally speed though not capacity, but it could be worth a go

 

[RayVM]

The CPU is fine, slots all work every time I test them with ram installed in various ways. All ram work every time as well, they just won't play well together when all four are installed in their pairs. I am going to look at their voltages next and see how far I get with that.....

 

[wookiee87]

regarding what you've said, that the ram works in dual channel mode when each kit is used separately I'd say it's your cpu, dual channel may be fine but running all 4 together the cpu doesn't like it hence only 3 stick show up, which cpu do you have?

there is one thing to try and that's overvolting the imc/vtt voltage, that controls the imc on the cpu so upping it may make all the ram show up, don't push it too far as you will cause fatal damage to the cpu!

 

[RayVM]

It's a i9 9900k. Been told the issue is more likely the kit, basically as they are not a 4x16 kit. The first pair were Samsung hardware, the second are Hynix too. Same part number, new ones have a higher revision number. Possible?

 

[wookiee87]

ahh if the kits of ram are not totally identical then that may explain it, mixing them can cause issues as Samsung are pretty dam good, hynix not so much.
manufacturing tolerances may be too far apart, have you tried all 4 at a lower ram speed to check if they all show up?

just out of interest what speed are the kits at?

 

[RayVM]

Sorry, should have mentioned it. Never had that issue before with any previous builds although I rarely added more ram. They are 3200 so run at 2333 from what I can see. The whole rig is geared up for serious overclocking but I haven't done that yet. Was hoping to do that once I got the 64gb of ram running. Is it maybe worth biting the bullet and buying a bigger kit?

 

[wookiee87]

if your ram is running that low and still not playing ball then somethings wrong, the kits obviously don't like each other, just a quick question do you need 64gb of ram? you could save cash and get high speed (3200-3600mhz) 32gb dual channel set which would do the job nicely

i have a trident z neo 32gb dual channel ram at 3600mhz on my build and its rock solid, for what i do i see around 20gb max but that was gaming and a tonne of web pages open (+50)

 

[RayVM]

You know, you are probably right. That's literally what I've just been reading when looking around for other kits. I do a lot of archviz and video work and fancied a decent boost, but would there be anything you'd recommend?

 

[wookiee87]

with ram kits it always best to get the tightest trimmings you can, depends on your budget but most people go for 3200mhz as you have above .

couple of brands come to mind

corsair
g skill (tridend z)
crucial

i personally like 3600mhz+ but those kits arn't for all, can be a real pain to run and timings are loose, my advice is go for a 3200mhz kit again and for the rgb bling go trident z, i have the neo version and they do look and perform very good, aim for cl15/cl16 @ 3200mhz and you should be good to go