[SOLVED] Can I put one more RAM Memory on my MOBO?

[dogegeo]

I have a AsRock B365 Pro4 MOBO with a Core I5-9400f on it, I currently have 2x4 HyperX Fury Black 2666Mhz and I want to put 4 more GB so I have 12GB, if I buy the same exact memory module will my pc read all 3 of them? or do I have to have 4x4 to read them all?

 

[kanewolf]

I have a AsRock B365 Pro4 MOBO with a Core I5-9400f on it, I currently have 2x4 HyperX Fury Black 2666Mhz and I want to put 4 more GB so I have 12GB, if I buy the same exact memory module will my pc read all 3 of them? or do I have to have 4x4 to read them all?

Your performance could decrease. That single DIMM won't be in dual channel mode. If you want more RAM, the best way is to buy a matched set of two 8GB DIMMs. Then give away, sell or reuse the 2x 4GB memory.

 

[Dj0gany]

You have the max chance of it working if you buy a new kit to replace the old ram(s).
Mixing ram doesnt mean its always going to work,especially if you buy different models.
Even if you buy the eaxct same ram kit with the exact same capacity,it still doesnt mean it will work together.
So i think your best option is to sell your existing 2x4gb kit,and buy a new 2x8gb kit.

 

[geofelt]

I see several issues:
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.
You can sometimes compensate for errors by increasing the ram voltage in the motherboard bios.

That said, intel is relatively tolerant of unmatched ram.
Your chance of success, I put at 90%.
Yes, your ram is unmatched despite the same part number.
Matching can only be done at the factory.
What is your plan B if the new ram does not play nice?

Next issue is that I know of no single DDR4 4gb ram sticks to buy.

If you should be able to find a 4gb stick that worked, 8gb would continue to run in dual channel mode and the odd 4gb in single channel mode. This is called flex mode.
Synthetic ram tests will show a decrease in performance, but you apps will actually benefit from more ram.

DDR4 rm is cheap enough.
I suggest you buy a 2 x 8gb kit that matches the specs of your current ram.
You will have guaranteed 16gb. Then try adding in your 2 x 4gb ram and see if it works.
If it does, great.
If not, keep the old ram as a spare or sell it.

 

[dogegeo]

I see several issues:
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.
You can sometimes compensate for errors by increasing the ram voltage in the motherboard bios.

That said, intel is relatively tolerant of unmatched ram.
Your chance of success, I put at 90%.
Yes, your ram is unmatched despite the same part number.
Matching can only be done at the factory.
What is your plan B if the new ram does not play nice?

Next issue is that I know of no single DDR4 4gb ram sticks to buy.

If you should be able to find a 4gb stick that worked, 8gb would continue to run in dual channel mode and the odd 4gb in single channel mode. This is called flex mode.
Synthetic ram tests will show a decrease in performance, but you apps will actually benefit from more ram.

DDR4 rm is cheap enough.
I suggest you buy a 2 x 8gb kit that matches the specs of your current ram.
You will have guaranteed 16gb. Then try adding in your 2 x 4gb ram and see if it works.
If it does, great.
If not, keep the old ram as a spare or sell it.

i have a 2x4 kit right now, and from the site i bought all my pc parts from, they sell 4gb ram sticks, not in a kit, single ram stick, and my plan b is to either return it and get another 2x4 kit or just buy another 1x4

 

[geofelt]

So long as you have a return option, plan B is ok.
Take the time to test the ram.
Run memtest86
It boots from a usb stick and does not use windows.
You can download the free edition here:

Memtest86+ | The Open-Source Memory Testing Tool

Memtest86+ is an advanced, free, open-source, stand-alone memory tester for 32- and 64-bit computers (UEFI & BIOS supported)

www.memtest.org

If you can run a full pass with NO errors, your ram should be ok.

Running several more passes will sometimes uncover an issue, but it takes more time.
Probably not worth it unless you really suspect a ram issue.