Question Is using 2 slots better than all 4?

[ingeborgdot]

I have some good memory that is 5 years old. I would like to bump up to 32GB from the 16GB that I have. I have read that it is best to only use 2 slots instead of 4 though. How much does it effect the memory speed by adding another 2 ports for a total of 4? Should I just buy new stuff? This will be used in an unRAID server running Plex. I have gotten multiple people saying that 16 should be enough, but if you decide to do this or that, you may want more.
Here is what I have now. CORSAIR Vengeance LED 16GB (2 x 8GB) DDR4 2666 (PC4 21300) Memory (Desktop Memory) Model CMU16GX4M2A2666C16
Suggestions? Thanks.

 

[Tech Junky]

For a single use box like unRAID/ NAS the idea is to keep the costs down since it just sits there 24/7.

I have 16gb in my Linux server that does a whole lot more than just act as a NAS and it only uses 4gb typically. The price difference between 8 or 16 was minimal for the boost in capacity with redundancy of two sticks.

 

[igor_kavinski]

If you have the RAM sticks available and you have no use for them, by all means try populating all four slots of the mobo with your sticks and see how it performs. Just be sure to run a full memtest downloadable from memtest.org and confirm that your RAM is fully stable.

 

[ingeborgdot]

I don't have 2 more sticks. After looking, I can't find any, or at least any that would be worth buying. The price they want would be stupid for me to buy. It would be best to buy 2 new sticks of 16x2 for almost the same price they want for the 2x8.
I am getting an Z690 board from MSI. MSI Pro Z690-A DDR4. I haven't bought it yet, but will in a couple of weeks.

 

[C1]

If your MB is not quad channel capable (most are not), running two sticks should be fine.

(Make sure that it's good quality memory.)

2 vs 4 RAM Modules - Are There Any Differences?

Will you see any noticeable differences in performance when choosing either 2 or 4 RAM Modules for your PC? We've taken a closer look.

www.cgdirector.com

Whats faster 2 sticks or 4 sticks?

Should I go 2 sticks of 32Gb or 4 sticks of 16Gb? Ryzen 9 3900 on a B450 Steel legend, if it matters... Thanks!

linustechtips.com

 

[ingeborgdot]

I would think the MSI Pro Z690 A would be quad capable, but you never know.
Now, after looking, I can't find anything worth getting that would match what I already have. It's either keep it at 16GB, or buy new. If I buy new the 32GB is really not that much more than the 16GB.

 

[igor_kavinski]

I would think the MSI Pro Z690 A would be quad capable, but you never know.

Quad channel only if you go with DDR5 (At the slot level, two DIMMs do dual channel. At the DIMM level, each DIMM also does dual channel within its memory chips). With DDR5, you get 4 32-bit channels. With DDR4, you get two 64-bit channels. For four 64-bit channels of DDR4, you have to buy an expensive workstation with Ryzen Threadripper or Intel Xeon CPU.

 

[C1]

Here's the user manual for PRO Z690-A WIFI/ PROZ690-A motherboard.

https://download.msi.com/archive/mnu_exe/mb/M7D25v2.0.pdf

This MB supports dual channel mode.
- 4x DDR5 memory slots, support up to 128GB*
▪ Supports JEDEC standard DDR5 4800/ 6400+ (OC) MHz
▪ Supports Intel® XMP 3.0 OC
▪ Supports Dual Controller Dual-Channel mode
▪ Supports non-ECC, un-buffered memory

* Please refer www.msi.com for more information on
compatible memory.


Good Luck

 

[igor_kavinski]

By the way, any existing DDR4 sticks you may have won't work in a DDR5 mobo.

 

[ingeborgdot]

I'm not planning on DDR5. DDR4 is what I'm looking at.

 

[Tech Junky]

I'm not planning on DDR5. DDR4 is what I'm looking at.

Then you need a /D4 Mobo.

 

[ingeborgdot]

Yes, that's what I'm buying, a DDR4 motherboard.
MSI PRO Z690-A DDR4 ProSeries Motherboard (ATX, 12th Gen Intel Core, LGA 1700 Socket, DDR4, PCIe 4, CFX, M.2 Slots)

https://www.amazon.com/MSI-DDR4-ProSeries-Motherboard-Socket/dp/B09GLD6LYW/?_encoding=UTF8&pd_rd_w=KF83X&content-id=amzn1.sym.8cf3b8ef-6a74-45dc-9f0d-6409eb523603&pf_rd_p=8cf3b8ef-6a74-45dc-9f0d-6409eb523603&pf_rd_r=SYGQ4DMRK3W57CTHMPGP&pd_rd_wg=aDgJi&pd_rd_r=8a16ded6-75a8-4eca-8e8d-e85f98cb5798&ref_=pd_gw_ci_mcx_mi

 

[Tech Junky]

Just making sure since there seems to be confusion as it comes in both. Again you don't need to upgrade the ram if you look at the system stats. It should be fairly low even when moving big data.

 

[tcsenter]

Better for some slight performance advantage especially for overclocking the memory. The real impact of doubling RAM will likely more than nullify any performance loss due to stepping down one speed/frequency tier and relaxed timings. But YMMV...

 

[Insert_Nickname]

Just a few basics.

A "slot" in this case refers to a DIMM slot. DIMMs can be either single or double sided* (1 or 2 ranks). More ranks per channel improves total bandwidth per channel, while less ranks per channel improves latency and potentially the frequency you can run them at.

Lesser capacities (for a given memory generation) are often single rank due to needing less physical chips for reaching the required capacity. With higher capacities being the opposite. With DDR4 there are 8GB DIMMs which are dual rank, but they're getting hard to find.

So what's best really depends on which is more important to your workload, latency or bandwidth.

*In ye olde days this was quite literal. There'd be memory chips on both sides of the DIMM. Allowing for easy identification. Today, it's internal in the DIMMs.

 

[ingeborgdot]

Yeah, again I get good advice from all of ye old fellers in here. Can't ask for better guys. My thinking now, is that I'm selling my motherboard, and cpu anyway. Why not sell the memory also. I will at least get half of what I pay for my new memory. I can't believe what people are willing to pay on eBay. I know many will think I'm crazy, but I like to tinker, and upgrade every once in awhile. I should do it more often, then I wouldn't be so much out of the loop when I come to do it again, but it is what it is.
I have a MSI Z270 SLI PLUS LGA 1151 board, Intel Core i7-7700 3.6, and CORSAIR Vengeance LED 16GB (2 x 8GB) DDR4 2666 (PC4 21300) Memory Model CMU16GX4M2A2666C16. I was checking on eBay, and I can help pay for some of the new gear I'm getting with this older stuff. I will at least get half of what I pay for new after shipping and deductions on eBay.

 

[Tech Junky]

I do system rebuilds when there's a significant change to the tech built into the CPU or board which right now is about every 2-3 generations. If you sell all three in a bundle you could get more for it than piecing it out. However since it's compatible with the new board and CPU you could save money and just move it over. It's up to you but 32gb is overkill for a NAS.

 

[ingeborgdot]

Tech Junky, you always piss me off. You burst my bubble with all of this stuff that makes sense. Dammit, quit making sense.
Yeah, you are probably right.
So, you think I could get more, if I bundle my board and cpu together? I don't see a lot of people doing that though.
Thanks again for keeping me in check. I'll just keep the memory for now, and find out how it goes for what I do. Have a great day.

 

[Tech Junky]

If you bundled all of it ram/CPU/board you could potentially get more for it as the person buying it could have a system ready to put into a case with the other parts they need. Then again you might get that cheap AF bidder and not. It's always a gamble on ebay.

 

[BonzaiDuck]

I'm surprised nobody mentioned the performance limitations of 4x vs 2x modules.

OK. If the memory is flawless and passes something like HCI Memtest86 64-bit or similar through say 300% -- and as desired only 2x sticks at a time -- and IF -- the kits are essentially the same make, model and timings, you should be able to run them at the spec speed (even "OC" as many kits are made and spec'd). You should be able to use the XMP profile so the timings are automatically set to the spec.

But. You likely will not be able to get them to run at a command-rate of CMD = 1; you will only be able to run them at the stock default value of CMD =2.

I hadn't seen much in back-and-forth exchanges or disagreement about this, but it is my personal judgment that you can "sense" the bump in speed from CMD=2 to 1. You may have to tweak the VCCIO voltage just a tad, possibly fine-tuning also the VCCSA setting. They may name these settings differently with current-gen motherboards -- I wouldn't know. The VCCIO is the IMC voltage or integrated memory controller voltage. You can sort the rest of it out.

I've got a 16GB = 8x2 GB kit that is G.SKILL Trident-Z 14-14-14 3200 DDR4, model code-suffix "GTZ". I later acquired a pair of LED G.SKILLs, Trident-Z 14-14-14 3200s, but with the LED lights, code suffix GTZR. No problem, and I can get a total of 48GB RAM without much doing anything but to test the VCCIO stability and maybe bumping it up about 0.05 V at most and well within the safe limit for those modules.

Maybe tomorrow I'll break open the box and slip in the 8x2 kit, and then put OCCT on a 3-hour memory test and end of story.