Question Z97 does not post with more than 16GB RAM

Sep 5, 2019
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Started putting a Z97 build together and I'm trying to install 32GB RAM. However it's not posting unless I use only 8GBx2 or 4GBx4. I've tried 24GB and no luck.

All my RAM works. I've tested using a P55 and it posts with up 32GB.

Z97 has been factory reset and reflashed to latest BIOS.

Hardware:

i7 4790k
Gigabyte Z97X-Gaming 7

Corsair Dominator Platinum 4GBx2 1866MHz ver4.29
Corsair Dominator Platinum 4GBx2 1866MHz ver8.16
Corsair Dominator Platinum 8GBx2 1866MHz ver5.29
Corsair Dominator Platinum 8GBx2 1866MHz ver8.22
 
The CPU should be ok, but I did buy it from a guy that said his motherboard got fried by a faulty PSU. There was no wear or damage on the pin contacts either. It's been working fine so far.

It was a custom PC build so I don't think it was a iMac CPU.

I'll try to find another LGA1150 CPU to test with.
 
Started putting a Z97 build together and I'm trying to install 32GB RAM. However it's not posting unless I use only 8GBx2 or 4GBx4. I've tried 24GB and no luck.

All my RAM works. I've tested using a P55 and it posts with up 32GB.

Z97 has been factory reset and reflashed to latest BIOS.

Hardware:

i7 4790k
Gigabyte Z97X-Gaming 7

Corsair Dominator Platinum 4GBx2 1866MHz ver4.29
Corsair Dominator Platinum 4GBx2 1866MHz ver8.16
Corsair Dominator Platinum 8GBx2 1866MHz ver5.29
Corsair Dominator Platinum 8GBx2 1866MHz ver8.22
Did you install the Modules correctly? Should be each kit in different colored slots. So that would be 4GB in the Black slots and 8GB in the Gray slots. I know that on older Intel boards I own, installing different kit sizes can either make the system not boot or give the expected result of single channel only. You may also have to run looser timings to get 4 modules of different sizes to run correctly.
 
Yes I've made sure the same kits are in the same channel. They should be only sitting at 1333MHz when I install them since XMP is turned off. I'll try to lower the timings manually, but I'm really starting to think that the CPU has some damage. I'll probably need buy another CPU for testing since I don't know anyone that runs 4th gen.
 
Yes I've made sure the same kits are in the same channel. They should be only sitting at 1333MHz when I install them since XMP is turned off. I'll try to lower the timings manually, but I'm really starting to think that the CPU has some damage. I'll probably need buy another CPU for testing since I don't know anyone that runs 4th gen.
You said you are on your second 4790K, it could very well mean you have a bent pin or the motherboard has a fault in the memory slots or elsewhere. It probably isn't a faulty CPU.

You could try changing which slot banks are being used by alternating between the Black and Gray slots and have only one module of either type in a slot and check that every slot is working. You could also try cleaning the the memory slots with a brush or some canned air.
 
I'm not on my 2nd i7 4790k, that was someone else responding to my problem. Also, the problem isn't whether my RAM slots aren't working, they register 4GBx4 and post.

The reason why I haven't ruled the CPU out is that the person I bought it from said that their motherboard died from a bad PSU. While the CPU functions, it's possible that a part of it that allows the CPU to work with RAM greater than 16GB was damaged.

My motherboard could also be faulty, I did buy it preowned as well. But until I can find someone that has both a LGA1150 motherboard and CPU that I can test with, I can't really do much.
 
I'm not on my 2nd i7 4790k, that was someone else responding to my problem. Also, the problem isn't whether my RAM slots aren't working, they register 4GBx4 and post.

The reason why I haven't ruled the CPU out is that the person I bought it from said that their motherboard died from a bad PSU. While the CPU functions, it's possible that a part of it that allows the CPU to work with RAM greater than 16GB was damaged.

My motherboard could also be faulty, I did buy it preowned as well. But until I can find someone that has both a LGA1150 motherboard and CPU that I can test with, I can't really do much.
Your thread got hijacked! 😛 I honestly didn't even notice it wasn't you and I must have got myself confused looking through the comments.

When you reset the bios, were the modules still on the board or had you already removed them? I still doubt the CPU is damaged. It really just sounds like the motherboard doesn't allow for 2x4 and 2x8 at the same time or just those kits. If you were able to get into the BIOS you could likely just lower the speed to 1600 and set the timing to 9-9-9-24 2T.

I have an Asrock Fatal1ty Z97X Killer I got from Newegg for $95 new two years ago for my old HTPC/encoder/server and I had at one time been using two G.Skill kits. A 2x4 (F3-12800CL9-8GBXL) and 2x8 (F3-1600C9D-16GXM) that would only work at CL10 until I upgraded to 32GB with a second 2x8 of the same kit that came with my used i7-4770S. Those two 16GB kits worked at 9-9-9-24 2T without issue.

So you could look at getting different memory as well as a different board and CPU on eBay or amazon. Just remember to be careful getting the z87 or other 80 series boards because they need to be flashed to support a 4790k.
 
I think when I reset the BIOS I either had only 2 sticks in or they were removed. I do have 2 older Corsair kits that are 2GBx2 1600MHz. If they can boot in the motherboard, I'll try running them in a 8GBx2 + 2GBx2 config.
 
Ram is sold in kits for a reason.
A motherboard must manage all the ram using the same specs of voltage, cas and speed.
The internal workings are designed for the capacity of the kit.
Ram from the same vendor and part number can be made up of differing manufacturing components over time.
Some motherboards, can be very sensitive to this.
This is more difficult when more sticks are involved.

Try increasing the ram voltage in the bios. Sometimes that can get disparate sticks to work.
I would try the 2 x 8gb pair first.