Question Z390-F not running all 4 ram slots together

Apr 5, 2020
15
0
10
0
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, went 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. So, all slots seem to work and all RAM sticks works. Can't fine anything in the BIOS to suggest an issue either, perhaps a setting somewhere? Although j have reset the BIOS multiple times. Any ideas?
 

kanewolf

Titan
Moderator
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, went 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. So, all slots seem to work and all RAM sticks works. Can't fine anything in the BIOS to suggest an issue either, perhaps a setting somewhere? Although j have reset the BIOS multiple times. Any ideas?
Mix and match RAM has no guarantee of working as a set, unfortunately. You can start by ensuring that your RAM is clocked at 2133 or 2400. You might add a little bit of voltage. It is going to be trial and error. Vendors sell matched sets or DIMMs for a reason. THEY have done that trial and error and guarantee all the parts to work as a set.
 
Apr 5, 2020
15
0
10
0
Mix and match RAM has no guarantee of working as a set, unfortunately. You can start by ensuring that your RAM is clocked at 2133 or 2400. You might add a little bit of voltage. It is going to be trial and error. Vendors sell matched sets or DIMMs for a reason. THEY have done that trial and error and guarantee all the parts to work as a set.
That's the thing, they are the exact same RAM - 16gb 3200 sticks. Been down that long road before of mixing them, never again. Beginning to think it is the voltage or speed that needs set though?
 

kanewolf

Titan
Moderator
That's the thing, they are the exact same RAM - 16gb 3200 sticks. Been down that long road before of mixing them, never again. Beginning to think it is the voltage or speed that needs set though?
They may be the same part number even the same components. BUT there is variability. That is what matching does. Minimizes the variability.
 
Apr 5, 2020
15
0
10
0
See what you mean actually. Would XMP set its own limits for them? Or literally trial and error and see what works best?
 

kanewolf

Titan
Moderator
See what you mean actually. Would XMP set its own limits for them? Or literally trial and error and see what works best?
Assuming they are all the same part number then they are guaranteed to work as pairs. Anything else is trial and error on your part.
XMP would attempt to set them all the same and be the worst possible choice because that is a higher clock speed.
 
Adding extra memory to existing memory has no guarantee to be compatible together.

Since you can make any combinations you want, you can do your own compatibility testing with no guarantees.

XMP profiles are for one kit, not multiple kits.
 
3200 speed ram is technically 2400 default ram of better quality that can be overclocked to each 3200 speeds. Likely at 1.35v.
Go into the bios and try raising the ram voltage from 1.35v a bit at a time to see if you can get it all to work. I would not go past 1.45v.
You may need to lower the speed below 3200.

Also, check to see if there is a motherboard bios update that might impact ram.
 

Third-Eye

Distinguished
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, went 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. So, all slots seem to work and all RAM sticks works. Can't fine anything in the BIOS to suggest an issue either, perhaps a setting somewhere? Although j have reset the BIOS multiple times. Any ideas?
Have you tried pulling the CPU and reseating it? You might have the wrong pressure on the CPU from the heatsink, causing pins to slightly misalign. Moving the system around or installing and removing ram might also cause enough flex to mess with CPU pins in the socket.
 
Do not reseat a cpu without a good reason.
Motherboard sockets are designed for only up to 15 insertions.

Yes, a bent pin can cause a ram slot to be disabled, but in this case all slots seem to be working. The problem is not all 4 at the same time.
 
"No problems for the last 5 months, been a great build so far. "

When you make a poor choice of memory, here are a few things you can do:

Give memory more juice (higher DRAM voltage)
Lower Memory Clock Speed
Relax DRAM timings
 
Apr 5, 2020
15
0
10
0
That's what I thought, or that's what I ruled out as all slots work fine. A lot of testing ahead of me. Cheers
 
Apr 5, 2020
15
0
10
0
Not sure it was a poor choice, 32gb with an i9 9900K can't be a bad spec, all I could budget at the time. Workload demands more now though unfortunately. More juice may be the way to go though ;)
 
Apr 8, 2020
18
2
25
1
Once got a new motherboard that was missing a pin on the ram slot. it worked with a single DIMM, but not when all 4 slots were filled
 

ASK THE COMMUNITY

TRENDING THREADS