is it okay to use 2x16 gb ram with 2x8gb ram sticks in the same motherboard?

zmepe · February 27

im planning to upgrade to new ram and i want to know if i can get free 16gb ram with my new 32gb kit. same speeds same manifacturer just the new ram will be rgb thats it 3200mhz all across

BoomerDutch · February 27

Yes it can.

In fact i have different speeds ram sticks

And different manufacturers.

All it did is limit higher speed to lower speed ram *shrug*

Yes i understand this is not recommended but hey if it works who cares right.

8tg · February 27

It’ll work, generally speaking. Just dual channel gets weird after you hit 16gb of usage. Not really enough to notice for regular use cases but some very ram dependent workloads you would see a noticeable decrease in performance after 16gb is used.

BahnStormer · February 27

I am really not sure how anybody is able to answer this without information about the CPU (i.e. memory controller) or spec of the RAM (timings).

Which CPU is this and what is the spec of each proposed memory kit you want to add?

In principle adding 2x8Gb sticks and 2x16Gb in the system will work just fine, but it is a question of what compromises you will need to make to get it to run.

Also, question if you will benefit from 48Gb RAM, especially if you need to slow the RAM down to get it to work: gaming = no, large file video editing = yes.

Memory Brand and size of each pair of sticks is largely irrelevant, it is the underlying hardware (supported timings) and memory controller (CPU) that matter - you can get those details using something like CPU-Z.

If the RAM timings are identical, it will probably work on Ryzen 5000-series or later, albeit you might need to find a compromise on timings.... but most Ryzen 5000 are running 3600MT/sec, so there's a risk that you're running an older CPU, where the memory controllers are a lot more fickle, even at 3200MT/sec.

e.g. On my old Ryzen 7 2700X, I had a lot of trouble when I tried to add 2x 3200MT/sec sticks to my original 2x 3200MT/sec sticks and getting the RAM to run at the rated timings (3200MT/sec 16-18-18-36).

These were visually identical 16Gb Corsiar Vengance LPX kits (each was 2x 8Gb, with identical ratings).

The problem was that Corsair had decided to cut costs and downgraded from really high spec Samsung B-die on the first few generations of those memory modules to SK Hynix modules that only JUST met the spec. The memory controller on the CPU was struggling to blend together what were two very different sets of memory modules, even at the rated speeds.

I ended up with a choice of running the old 2x8Gb at 3200Mhz 16-18-18-36 timings (or a lot faster with some tuning!)... or the "new" kit at the rated timings (no more!).... or both together at a compromise speed 3133Mhz or CL18... with CL18 being MUCH slower for gaming!

I tried these again once I had upgraded to a Ryzen 5000 CPU, which seemed to handle the slightly "mixed" RAM at the advertised speeds a lot better, but I'd already decided to swap for lower latency memory by then anyway.

I read later that there were a lot of upgrades to the memory controller from Ryzen 2000 to Ryzen 5000.... not sure where Ryzen 3000 sits on that scale though.

Queen Chrysalis · February 27

Unless 32GB of RAM is insufficient for your use case (I’m almost certain it’s much more than sufficient if you’re upgrading from 16), you should sell that 16gb kit. The computer will work better with only the two 16gb dimms. Extra RAM does absolutely nothing if it isn’t needed.

zmepe · February 27

6 hours ago, BahnStormer said:

I am really not sure how anybody is able to answer this without information about the CPU (i.e. memory controller) or spec of the RAM (timings).

Which CPU is this and what is the spec of each proposed memory kit you want to add?

In principle adding 2x8Gb sticks and 2x16Gb in the system will work just fine, but it is a question of what compromises you will need to make to get it to run.

Also, question if you will benefit from 48Gb RAM, especially if you need to slow the RAM down to get it to work: gaming = no, large file video editing = yes.

Memory Brand and size of each pair of sticks is largely irrelevant, it is the underlying hardware (supported timings) and memory controller (CPU) that matter - you can get those details using something like CPU-Z.

If the RAM timings are identical, it will probably work on Ryzen 5000-series or later, albeit you might need to find a compromise on timings.... but most Ryzen 5000 are running 3600MT/sec, so there's a risk that you're running an older CPU, where the memory controllers are a lot more fickle, even at 3200MT/sec.

e.g. On my old Ryzen 7 2700X, I had a lot of trouble when I tried to add 2x 3200MT/sec sticks to my original 2x 3200MT/sec sticks and getting the RAM to run at the rated timings (3200MT/sec 16-18-18-36).

These were visually identical 16Gb Corsiar Vengance LPX kits (each was 2x 8Gb, with identical ratings).

The problem was that Corsair had decided to cut costs and downgraded from really high spec Samsung B-die on the first few generations of those memory modules to SK Hynix modules that only JUST met the spec. The memory controller on the CPU was struggling to blend together what were two very different sets of memory modules, even at the rated speeds.

I ended up with a choice of running the old 2x8Gb at 3200Mhz 16-18-18-36 timings (or a lot faster with some tuning!)... or the "new" kit at the rated timings (no more!).... or both together at a compromise speed 3133Mhz or CL18... with CL18 being MUCH slower for gaming!

I tried these again once I had upgraded to a Ryzen 5000 CPU, which seemed to handle the slightly "mixed" RAM at the advertised speeds a lot better, but I'd already decided to swap for lower latency memory by then anyway.

I read later that there were a lot of upgrades to the memory controller from Ryzen 2000 to Ryzen 5000.... not sure where Ryzen 3000 sits on that scale though.