mixing ram sticks.

[Sly]

Guys do u think its fine to mix single channel and dual channel ram sticks?Right now i have dual channel 8 gb ram(4+4) and im planning to upgrade my ram to 16.so is it ok if i add one more stick of 8 gb ram which will be running in single channel?will i get any problems for mixing dual channel and single channel ram?

[bunder]

Its just memory. Since you'll have 3 sticks you can only run in single channel mode

[Autumn_]

Put the 2x4GB sticks in one channel, and 1x8GB in the other, it will run dual channel. (8GB per channel.)

The worst you could get is the stick doesn't like the other sticks, but that's rarely the case.
You will however have the sticks running at the lowest speeds, and the highest timings, so match them up.

bunder님이 먼저 게시:

Its just memory. Since you'll have 3 sticks you can only run in single channel mode

Wrong, he will still be able to use it in dual channel mode, but if he configures it wrong, he will have 12GB in one channel, and 4GB in the other, so only 4 of that 12 from the first channel will be dual channel.
The other 8GB will run in single channel, afaik.

[Overseer]

RAM Modules have nothing to do with Memory Channels. You don't buy dual channel RAM, you buy 2 DIMMs in one kit. It all comes down to the board and how the modules are installed. You could have 4 DIMMs and install them all in one channel.
But if your board has only 4 slots on a Dual Channel board and you install 3 modules they will run in Dual Channel as 2 slots are electrically connected to 1 channel. There is no other logical way. Its just hard on the memory controller, as it has to time one channel that splits up into 2 modules, and time one channel that only connects to 1 module. So frequencies and sometimes even stability become a problem.

[Bad 💀 Motha]

This just needs the simple answer and nothing else.

Never mix any ram besides ram that matches, there was easy right. Common sense people!

[SeriousCCIE]

I had to mix memory, but I ended up mixing higher end memory with the memory I wanted to use, and running the higher end stuff at a somewhat lower setting.

Ultimately, for automagic configuration settings--and the stability it brings (if not always performance), get all the same and try not to mix and max if you don't have to.

I 'had' to, due to having one out of 8 of a matched set of 8 sticks for quad channel go bad due to what we can call misadventure. Not too unlike losing diskettes because the cat sat on them or something like that.

So, I had to get a replacement, and as luck would have it, no one sold 8 sticks of quad channel memory at a cheap price. I had to get something else, and opted for a smaller kit and rolled the dice.

I ended up having to use 6 of one type and 2 of the other, and then ran them all at the same speed. That worked, and has been stable for a few years now.


Configuration and timings and whatnot was very important to get right; it was a bit of a trial and error process as the XMP profiles never worked for me even when not mixing and matching; if at first you don't succeed, change the timings and try again...

[Bad 💀 Motha]

The only way to use an xmp profile is to install the slower ram of the mix in first, boot up, enable the xmp, save and shutdown. Then install the other ram, as those faster ram should be able to work at the lower frequency and whatever timings and voltage the slower ram uses via the xmp profile. Now if you try to get the slower ram to run above its specs to match the faster ram, this is often where problems will occur.

[Zireth]

It'll still work but it will only go as fast as the slowest stick of ram.

[Bad 💀 Motha]

It doesn't always work though. It is hit or miss. But why mix ram, seriously, buy matching ram. Why would you want any slower ram in the mix and defeat some of the reason you bought new ram, if the new ram is faster. Sure increasing the amount is always the better end of the deal, but why not run the ram as intended at per it's specs. Even if the bios posts amd os loads up ok, the system could be unstable with mixed ram

[_I_]

Overseer님이 먼저 게시:

RAM Modules have nothing to do with Memory Channels. You don't buy dual channel RAM, you buy 2 DIMMs in one kit. It all comes down to the board and how the modules are installed. You could have 4 DIMMs and install them all in one channel.
But if your board has only 4 slots on a Dual Channel board and you install 3 modules they will run in Dual Channel as 2 slots are electrically connected to 1 channel. There is no other logical way. Its just hard on the memory controller, as it has to time one channel that splits up into 2 modules, and time one channel that only connects to 1 module. So frequencies and sometimes even stability become a problem.

that would be dual ch, but only dual ch speeds for the 4+(8/2)g, and single ch for the remaining 4g

and also need to deal with mixing ram freq and timings

it would be best to get a 2x8g kit or a matching 2x4g kit

[Bad 💀 Motha]

Always do matching ram with at least 2 matching. If going beyond 2 modules, then do 4, never 3... not on a dual or quad channel board.

If you do 4 modules, they do not all have to be the same size, but it helps to have the same specs.

For example...
2x 4gb Corsair LPX ddr4 3200 Cas 16
2x 8gb Corsair LPX ddr4 3200 Cas 16

Now these 4 can work in dual channel mode if installed properly.
Such as installed like this...

Slot1= 8gb
Slot2= 4gb
Slot3= 8gb
Slot4= 4gb

[talemore]

Get another 4+4 and you get quadchannel.

[Autumn_]

talemore님이 먼저 게시:

Get another 4+4 and you get quadchannel.

No, you don't unless you have a HEDT CPU, regular desktop CPUs are limited to two channels.

[Bad 💀 Motha]

talemore님이 먼저 게시:

Get another 4+4 and you get quadchannel.

No such thing unless you have a workstation board like X299

[tacoshy]

bunder님이 먼저 게시:

Its just memory. Since you'll have 3 sticks you can only run in single channel mode

Not true. You can run full dual channel with 3 sticks. You simply have to put 2x4 GB in channel A and the 8GB in channel B. Dual channel requires both channels to have the same RAM capacity.
Also if you run with uneven channel capacity you not run in single channel, you run in flex mode.

https://steamcommunity.com/groups/Master_Race_Geeks/discussions/0/2747650363459040918/

[Viking2121]

Not quite the simple answer that you want, but Yes you can mix RAM.

Though mixing ram can have problems, BSOD's to random app crashes, or causing strange things in some apps.

I have a i7 920 with 2x Mushkin 8GB sticks paired with 2x Samsung 2GB sticks and that system has been running great.

Though I have had a system with 2x PNY sticks and tried pairing them with 2x Corsair sticks and that system refused to boot no matter what I did, both sets worked on their own flawlessly.