Mixing RAM, what's better, 32gb kit or 48gb mixed?

[Cor3000000323]

Hey,

I currently have 2 x 8GB sticks G.SKILL Ripjaws V Series in my PC. I was gifted 2 x 16GB sticks Vengeance RGB PRO SL from a 4 x 16GB kit by a friend (no idea why he's not using the whole kit).

Would it be better to use just the two 16gb sticks for 32gb or use the 4 sticks for 48gb for more performance but less stability I think? If so, what does that mean? Keep in mind that I know nothing about RAM specs and such, so I'm wondering what the actual consequences that I could experience be. If that can't be explained like that, eh, it's ok, it can't always be explained in simple terms.

Here are the specs for the different RAM sticks taken from the websites.
G.SKILL Ripjaws V Series 16GB (2 x 8GB) 288-Pin PC RAM DDR4 3200 (PC4 25600) Desktop Memory Model F4-3200C16D-16GVRB:

Spoiler

Memory Type DDR4
Capacity 16GB (8GBx2)
Multi-Channel Kit Dual Channel Kit
Tested Speed (XMP/EXPO) 2133 MT/s
Tested Latency (XMP/EXPO) 15-15-15-35
Tested Voltage (XMP/EXPO) 1.20V
Registered/Unbuffered Unbuffered
Error Checking Non-ECC
SPD Speed (Default) 2133 MT/s
SPD Voltage (Default) 1.20V

VENGEANCE RGB PRO SL High-Performance DDR4 DRAM:

Spoiler

Memory Series VENGEANCE RGB PRO SL
Memory Type DDR4
Memory Size 64GB (4 x 16GB)
Tested Latency 18-22-22-42
Tested Voltage 1.35V
Tested Speed 3600
Memory Color BLACK
LED Lighting RGB
Single Zone / Multi-Zone Lighting Dynamic Multi-Zone
SPD Latency 15-15-15-36
SPD Speed2133MHz
SPD Voltage 1.2V
Speed Rating PC4-28800 (3600MHz)
Compatibility Intel 300 Series,Intel 400 Series,Intel 500 Series,Intel 600 Series,AMD 400 Series,AMD 500 Series,AMD TRX40
Heat Spreader Anodized Aluminum
Package Memory Format DIMM
Performance Profile XMP 2.0
Package Memory Pin 288

I hope my question is clear and it hasn't been answered a thousand times.
Thanks a lot.

 

[mackerel]

2x16 3600 seems safest option, unless you know you have a workload that needs >32GB of ram where 48GB comes in.

Generally it works or it doesn't. Try it out, and if you have no problems enjoy.

 

[EarthDog]

What mack said.

I'd absolutely run the 2x16gb sticks alone though. They are slightly faster speed and you likely don't need the capacity or potential headaches that come along with mixing kits. Won't hurt to try all 4, but not sure it benefits you in any way either.

 

[WhitehawkEQ]

This is from the manual for 1 of my PC's
GA-X99-Desigare EX MB: Make sure that the motherboard supports the memory. It is recommended that memory of the same
capacity, brand, speed, and chips be used.
This applies to all MB's.

Also it may look like it works but end up reading the 8G ram twice making it look like 16G, I ran in to this back in the 80's with my 1st 8bit computer.
You can mix different speeds, but the faster ram will run at same speed that the slower ram runs at.
Oh 1 last thing, in most cases if your MB uses dual channel memory, max total ram is 32GB.

 

[Cor3000000323]

Thanks a lot for the answers.

I believe I'll use 32 to be safe, which is plenty anyway. I do some video editing, not all day long or professionally but still pretty consistently, but I doubt having 32 instead of 48 would drag down the sort of work I do to the point of being a big hinderance.

 

[mackerel]

Oh 1 last thing, in most cases if your MB uses dual channel memory, max total ram is 32GB.

I don't think that's been a limit at least in DDR4 era. DDR4 32GB modules have been supported for many generations so a typical dual channel system with 4 ram slots can have 128GB of ram. I've been running 64GB (4x16) in dual channel systems for several years. Here's a run I did on Skylake with 64GB: https://hwbot.org/submission/4371563_mackerel_y_cruncher___pi_10b_core_i7_6700k_17min_12sec_715ms
That particular bench in those settings needs >46GB so if you have less than that, you'll have a bad time. I don't have that system any more but it would be 7 years old now, so 32GB hasn't been a dual channel limit for at least that long.

 

[EarthDog]

Thanks a lot for the answers.

I believe I'll use 32 to be safe, which is plenty anyway. I do some video editing, not all day long or professionally but still pretty consistently, but I doubt having 32 instead of 48 would drag down the sort of work I do to the point of being a big hinderance.

All you need to do is look at your ram use when doing the work. If you're reach8ng it, consider mix and match.

 

[WhitehawkEQ]

I don't think that's been a limit at least in DDR4 era. DDR4 32GB modules have been supported for many generations so a typical dual channel system with 4 ram slots can have 128GB of ram. I've been running 64GB (4x16) in dual channel systems for several years. Here's a run I did on Skylake with 64GB: https://hwbot.org/submission/4371563_mackerel_y_cruncher___pi_10b_core_i7_6700k_17min_12sec_715ms
That particular bench in those settings needs >46GB so if you have less than that, you'll have a bad time. I don't have that system any more but it would be 7 years old now, so 32GB hasn't been a dual channel limit for at least that long.

I agree, newer systems can have more than 32GB in dual channel but seeing as Cor3000000323 did not tell us what his system spects are I went to default of 32GB max.

 

[EarthDog]

I agree, newer systems can have more than 32GB in dual channel but seeing as Cor3000000323 did not tell us what his system spects are I went to default of 32GB max.

IIRC, support for 128GB of dual-channel RAM (32GB DIMMs) on Intel came out (officially?) with Z390 a few years back. On the AMD side, X470 supported it with BIOS updates a few years back as well. I'd actually say the opposite... in most cases, boards support it unless it's a really old (read a few gens back) board/chipset.

For clarity, OP/Cor, please list your system specs or create a signature.

 

[don256us]

Hey guys. Do we know what MB he has? I may have missed it but I don't see it. While all of this advise is good general knowledge, do we have enough to adivse? Maybe.

I note that the two RAM kits have different speeds and CAS timings. In general, if you use both kits, the slower kit shoule really go in the first bank. Review your manual to know which bank that is.

Saying that, my limited testing showed that the computer really gets a boost if you use all channels for RAM. Dual channel, use two sticks, quad channel, use 4 sticks. If you are using all chanels, memory speed then becomes a greater factor. In your case, someone mentioned dual channel. Putting 1 16 GB in one channel and the other in the other channel, you have maxed out your gain.... to a point. Then going with faster RAM that your system supports will get you the rest of your speed gains.

Your MB may have 4 slots but only 2 channels. Once you install 2 sticks of RAM, the slower RAM will not increase speed and conversly reduce speed/performance.

I'm not sure that I explained myself very well here but if you only have a dual channel, keep with the 2 x 16GB and ditch the 2 8's.

If I knew the specifics of your system, CPU/MB, I might have a different view.

 

[EarthDog]

Good point, Don. I think I got what you said, regardless if advice (ice) and advise (eyes) threw me...

If he's got a quad channel platform (he's been running dual on it already if that's the case) using all four sticks may be best. In that case, I'd ditch all the sticks and buy a matching quad kit for the best results.

If he mixed and matched using all four sticks in dual channel and it did work, the only benefit he would get is if he used more than the 32GB (though slower all around it's still faster than paging out - even to an NVMe drive).

I'd like to know for curiosity's sake, but that doesn't change the advice from me otherwise.

 

[mackerel]

I agree, newer systems can have more than 32GB in dual channel but seeing as Cor3000000323 did not tell us what his system spects are I went to default of 32GB max.

Why 32GB? Has that ever been a limit for DDR4 systems? I already gave an example that the first consumer DDR4 system, Skylake, supports 64GB in the form of 4x16 as I've ran that personally. Before that we had X99 based but that's quad channel so besides the point. If you had a mobo with only two slots and no 32GB module support, then 32GB could be a limit, but OP sounded like they have the capability to run 4 sticks so again not relevant.

 

[don256us]

With all respect and shouts to my peeps... this is why we would want to know the CPU and MB.

 

[Cor3000000323]

Sorry for not including my specs the first time around. I just updated my signature and here they are as well:

Motherboard: ASRock B450M PRO4 AM4 AMD Promontory B450 SATA 6Gb/s Micro ATX AMD Motherboard
Chipset: AMD Promontory B450
Processor: AMD Ryzen 5 2nd Gen - RYZEN 5 2600X Pinnacle Ridge (Zen+) 6-Core 3.6 GHz (4.2 GHz Max Boost) Socket AM4 95W YD260XBCAFBOX Desktop Processor
Physical memory: G.SKILL Ripjaws V Series 16GB (2 x 8GB) 288-Pin PC RAM DDR4 3200 (PC4 25600) Desktop Memory Model F4-3200C16D-16GVRB
Graphics card: NVIDIA GeForce GTX 960 SSC 4GB
Storage: Kingston A400 480GB SATA 3 2.5" Internal SSD SA400S37/480G....... Western Digital WD5002AALX-00J37A0 ATA Device (500GB)....... Western Digital WD1002FAEX-00Y9A0 ATA Device (1000GB)
Wi-fi adapter: ASUS PCE-AC68 802.11ac Network Adapter
Power Supply: Corsair HX Series 750W
Case: Antec Nine Hundred Two v3
Operating system: Windows 10 Home 64bit
Monitor: Acer X233H bd 58.4 cm (23") 1920 x 1080 pixels Full HD Black

I'm reading on the website that the MB has dual channel. When running a quick test of video editing and some other background activity, I'm nearly maxing out the RAM of 16gb (I haven't installed the 32gb yet), it's fluctuating between 80 and 96 percent. In other circumstances the RAM usage could be greater, but probably not a great deal more to exceed 32gb, with my limited understanding of it.

Edit: Let me know too if something is missing in my specs or even if there's some unnecessary stuff.

 

[EarthDog]

With all respect and shouts to my peeps... this is why we would want to know the CPU and MB.

I would play Russian Roulette with the odds that his machine could run 32GB sticks.

ASRock B450M PRO4 AM4

*click*

Whew!

So....... same advice, 2x16GB sticks... verify use isn't over 32GB and you're all set!

 

[don256us]

Yeah OK. You actually made me lol. I know when I've been got.