Single vs dual channel ram question

[volk06]

I have a desktop computer that currently has 2x4gb 3200 ram. I’m running out of ram with having multiple windows and programs going. I like to also do some light gaming periodically but have a dgpu.

I can either buy 2x8gb 3200 or I can buy a single stick of 16gb 3200 $30 cheaper and run 1x4 and 1x16 for a total of 20gb vs the 16gb of the 2x8. Now I know that with the 4 and 16, I’d have 8gb in dual and 12 in single channel.

I’m debating which route I should go. More total ram or more in dual channel but less overall. Does it really matter in the end?

 

[BMW Dom]

2x8 sounds about right.
What kind of work are you doing? What program?

 

[volk06]

2x8 sounds about right.
What kind of work are you doing? What program?

A little bit if everything. Quick books, excel, canva, chrome (ram hog), a few video games sprinkled in, some photos editing for the business video displays, solid works and blue beam, working from home, etc. Have plenty of cpu power and dgpu so far, but ram being close to maxed out is happening more frequently.

 

[BMW Dom]

A little bit if everything. Quick books, excel, canva, chrome (ram hog), a few video games sprinkled in, some photos editing for the business video displays, solid works, working from home, etc. Have plenty of cpu power and dgpu so far, but ram being close to maxed out is happening more frequently.

How many ram slots are on your motherboard? Also: AMD or Intel?

 

[volk06]

How many ram slots are on your motherboard? Also: AMD or Intel?

2 slots can easily go to 32gb, maybe 64 but that’d be way overkill. Ryzen 5300g and nvidia 1660 super.

 

[BMW Dom]

2 slots can easily go to 32gb, maybe 64 but that’d be way overkill. Ryzen 5300g and 1660 super.

16 GB shoudl be fine. Unless you want to go 32 GB. I would compare the costs and think about future proofing.

 

[dwasifar]

My experience is that dual channel is unreliable when the ram sticks don't match. I'd go with the 2x8.

 

[volk06]

16 GB shoudl be fine. Unless you want to go 32 GB. I would compare the costs and think about future proofing.

I’ll be getting at least 16gb. Just debating on 16gb or going the 20gb route.

 

[volk06]

My experience is that dual channel is unreliable when the ram sticks don't match. I'd go with the 2x8.

This is good to know. Thanks!

 

[BMW Dom]

I don't think that the 16 and 4 will work in dual channel mode

 

[blupupher]

With Ryzen you take a huge hit if you go single channel or non identical capacities.
Either get another set of 2x4 3200 if you have 4 slots, or if you just have 2 slots, go 2x8.

 

[volk06]

I don't think that the 16 and 4 will work in dual channel mode

They should, but it’d only be 8gb in dual and 12 in single channel but sounds like it’s not stable.

 

[volk06]

New dual channel ram it is. Now to see if I want to spend double for 2x16 instead of 2x8.

 

[DemoFly]

4 and 16 would be 20GB in Single channel.

I personally wouldn't splurge on 32GB when DDR5 is just around the corner.

I'm a huge nerd with an expensive computer running many programs and I am just fine with 16GB of RAM. Save that money and put it towards more solid state storage.

 

[volk06]

Thanks everyone. It appears I was misinformed regarding the 20g single/dual ram usage.

 

[vavavroom]

For best performance you should use both RAM slots and matching memory. For example. 2x 8GB RAM will outperform 1x16GB RAM in terms of speed. Same brand and model RAM.

 

[ripcord]

Contrary to all the advice given here, single channel mode will make a negligible difference for normal daily use. The only real area where it makes a difference is running certain highly demanding video games. For the vast majority of workloads, the single channel penalty will be between zero and a few percentage points.

Memory bandwidth is rarely the bottleneck.

 

[y_p_w]

Not really. Generally more RAM is better than trying to match them. It used to be assumed that the chipsets would enter into some magic "dual channel" mode where they would magically double the potential speed by operating in parallel. As in every operation would be mirrored across both channels, like suddenly it's 128 bits wide rather than 64. Apple enthusiasts used to go crazy over it, including some who were hoping that the built-in RAM would enter that mode with just additional RAM matching the exact capacity as built-in.

That being said, Intel chipsets are rather convoluted. Even without exactly matched memory modules, they should theoretically be able to operate in partial dual-channel mode (Intel calls it "Flex mode") up to the capacity of the smaller module. But dual-channel isn't a simple task of operating both at the same time simultaneously. They actually "interleave" where there can be a heads up and the chipset can address one channel in anticipation. The benefit in terms of speed will just be getting ahead of the latency for the first read when bouncing from one channel to the other. But it's not truly operating them in parallel. However, they are operating together where

https://www.intel.com/content/www/us/en/support/articles/000005657/boards-and-kits.html

I used to play around with memory configurations on my old (Intel) Mac using DDR2 SO-DIMMs. I had a variety of different modules with different capacities and different speeds, including the 512MB x 2 modules that came with it, some modules (OEM was actually Patriot-branded) I pulled from an Toshiba laptop, and newer modules that I purchased. I couldn't test for speed, but everything at the very least works and got registered. And if I placed any module of a lower speed, both modules defaulted to that lower speed.

 

[PandaBear]

8+8 will definitely be faster if you don't use more than 16GB, but if your use case is 16-20GB then obviously the 4+16 works better for you.

Having said that, for GAMING, you are likely going to use mostly the CPU + GPU and the memory bandwidth of dedicated GPU and the GPU performance would likely be the bigger deal, along with the number of core and frequency of your CPU. If you are using the integrated graphics on your Ryzen alone then you absolutely would need the dual channel.

In your case 5300g + 1660, you likely would be fine going 4+16. In my dad's 4700G with only VEGA graphics (or if you are going to sell your GPU and only use 5300g alone), definitely 8+8.

 

[y_p_w]

I brought up Intel chipsets because they provide more details on how "dual-channel" works in typical consumer-grade PCs. Have no idea what Nvidia chipsets do, although suspect that they're not all that different.