Going To 64GB RAM (Dual Rank and Dual Channel Question)

deadman_uk

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My PC was pre-built by PC Specialist during the times where GPUs were very hard to get hold of. I will be replacing my 6700 XT with an NVIDIA RTX 4090 in late June / early July from PC Specialist via their upgrade feature (their prices are the cheapest I can find). I have the option of buying another pair of DDR4 2x 16GB RAM sticks while I am at it. My question is relating to Dual Channel and Dual Rank. I don't really understand these terms but I understand that using 4 DIMMS instead of 2 may put one or both of these into single mode. Is this what will happen? Is this going to affect performance? The reason why I am considering jumping from 32GB to 64GB is I use Photoshop, Lightroom and will soon use Stable Diffusion so the extra RAM may be useful to smooth things out. Would appreciate comments.
 

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I am running 4x 16GB sticks in mine and it's still dual channel and dual rank.
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I think I read that if you have single rank dimms, running 4 sticks will be like dual rank or something along those lines, but you already have dual rank ram so just get the same set, or buy a 64GB kit and sell the old set.
I am running a Corsair 64GB kit and used my old ram in a new lower end build.
Also, I sold my 5800X system to a friend a few months ago and he wanted to up the ram to 64GB and I bought an identical Corsair kit but for some reason I couldn't get the machine to post with the ram set to 3600Mhz. It was stable at 3600Mhz with either pair of sticks and 2666 with 4 sticks.
 
I am running 4x 16GB sticks in mine and it's still dual channel and dual rank.
View attachment 571467

I think I read that if you have single rank dimms, running 4 sticks will be like dual rank or something along those lines, but you already have dual rank ram so just get the same set, or buy a 64GB kit and sell the old set.
Yes the ram I'd buy would be exactly the same brand and model. Hmm interesting. I never really understood it.
 
My PC was pre-built by PC Specialist during the times where GPUs were very hard to get hold of. I will be replacing my 6700 XT with an NVIDIA RTX 4090 in late June / early July from PC Specialist via their upgrade feature (their prices are the cheapest I can find). I have the option of buying another pair of DDR4 2x 16GB RAM sticks while I am at it. My question is relating to Dual Channel and Dual Rank. I don't really understand these terms but I understand that using 4 DIMMS instead of 2 may put one or both of these into single mode. Is this what will happen? Is this going to affect performance? The reason why I am considering jumping from 32GB to 64GB is I use Photoshop, Lightroom and will soon use Stable Diffusion so the extra RAM may be useful to smooth things out. Would appreciate comments.
Stop worrying.

2 memory kits will nearly always work together, but you will be limited (speed wise) to the slower of the two.
 
Stop worrying.

2 memory kits will nearly always work together, but you will be limited (speed wise) to the slower of the two.
The slower of the two? but both my original kit and the purchase will be the same speed, model etc unless you mean what Zepher is saying about they may not be able to get to 3600mhz overclock?
 
The slower of the two? but both my original kit and the purchase will be the same speed, model etc unless you mean what Zepher is saying about they may not be able to get to 3600mhz overclock?
he means if you put in slower ram, the faster ram will run at the slower speed, which won't apply to you if you buy the same ram you already have.
The issue I had could probably be fixed by playing more in the BIOS with the voltages but I didn't have time to mess with the machine before he had to leave with it.
 
he means if you put in slower ram, the faster ram will run at the slower speed, which won't apply to you if you buy the same ram you already have.
The issue I had could probably be fixed by playing more in the BIOS with the voltages but I didn't have time to mess with the machine before he had to leave with it.
But why would the RAM be slower if I am buying the same brand and model? I understand no two kits are exactly the same even if their specs say so. I'm not going to know until I try it right?
 
But why would the RAM be slower if I am buying the same brand and model? I understand no two kits are exactly the same even if their specs say so. I'm not going to know until I try it right?
His comment was about mixing two different speed kits, like 3200 and 3600.
Just buy the second kit and put it and see if you can get it all to run at 3600Mhz.
 
His comment was about mixing two different speed kits, like 3200 and 3600.
Just buy the second kit and put it and see if you can get it all to run at 3600Mhz.
My bad, I didn't make clear in my original post that the RAM I am considering buying is exactly the same (in name, model, speed) to my current. If I have some spare cash left over when I buy my 4090 I'll get another 32GB. I was just worried that I won't have dual rank and dual channel.
 
lookie here for some info:

https://www.cgdirector.com/single-rank-vs-dual-rank-ram/

It basically comes down to 2 things:

A) What configuration your mobo supports... most, but not all, current/recent memory controllers can handle dual/dual setups, others can not... It would be a good idea to read thru the manual & specs for yours (or contact the mfgr) before buying anything...
B) Which set-up gives you the best performance....which in your use case, would probably be with 2 x 32GB sticks, since PS & LR are more sensitive to the amount of ram vs a tad less bandwidth, but I don't know how Diffusion would react...

If you do decide to go with 4 sticks, I would get them all in a new 64GB set, then sell the current ones, just to be certain that they all match exactly..

Good luck regardless :D
 
lookie here for some info:

https://www.cgdirector.com/single-rank-vs-dual-rank-ram/

It basically comes down to 2 things:

A) What configuration your mobo supports... most, but not all, current/recent memory controllers can handle dual/dual setups, others can not... It would be a good idea to read thru the manual & specs for yours (or contact the mfgr) before buying anything...
B) Which set-up gives you the best performance....which in your use case, would probably be with 2 x 32GB sticks, since PS & LR are more sensitive to the amount of ram vs a tad less bandwidth, but I don't know how Diffusion would react...

If you do decide to go with 4 sticks, I would get them all in a new 64GB set, then sell the current ones, just to be certain that they all match exactly..

Good luck regardless :D
I have a ASUS Crosshair VIII Hero motherboard but will have to check later about that memory controller (unless you know and can tell me). The site I am buying from only do 16GB sticks not 32GB so can't go 2x32GB unfortunately, it's only 4 stick and I am not sure if they would just bundle 2 separate kits of 2x16GB together. hmmmmm....
 
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