16GB matched vs 32 GB unmatched

DAS

DAS

DAS

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Hi

I am look to upgrade my PC and wanted some advice on RAM. I have never noticed real world differences with RAM speeds like I do with GPUs or storage.

I am working on the basis that 32GB of new RAM is overkill, so was going to get 2 new 8GB sticks. However, I already have 2 other 8GB DDR4 sticks and I know that mixing unmatched sets is not recommended.

My question is :

If I added my existing 16GB to the new 16GB, would I see better overall performance from 32GB of mixed RAM compared to just the new 16GB matched pair. That assumes DDR4 – what about if the new pair were DDR5?

If I went with the unmatched 32GB, could I enable XMP?

Thanks
 
You can't put DDR4 and DDR5 together .

Mixing ram does work but not guaranteed to be compatable, useing 2 diffrent brands that have different timming the memory will run at the slowest timings or speed including xmp profile so yes you can use it..

2 sticks is easier to run at rated speed than 4 sticks.
 
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RAM can be a bit temperamental. Personally I'd just sell your old sticks and buy a new kit. It's very cheap at the moment, even 2x16GB, you'd avoid a lot of potential headaches that way.
 
Thanks for the replies. I realise that you cannot mix DDR4 and DDR5, my almost rhetorical question was whether 32GB of mixed DDR4 would be better than 16GB of DDR5. I accept that the best solution is to buy new memory (16 or 32), though I won't get much for my od RAM.

Thanks
 
DAS said:
Thanks for the replies. I realise that you cannot mix DDR4 and DDR5, my almost rhetorical question was whether 32GB of mixed DDR4 would be better than 16GB of DDR5. I accept that the best solution is to buy new memory (16 or 32), though I won't get much for my od RAM.

Thanks
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If you run out of RAM then more slower RAM will be better. I'd say now is a good time to buy as I can only see it going up as there was an oversupply and they have cut back production now.
 
DAS said:
my almost rhetorical question was whether 32GB of mixed DDR4 would be better than 16GB of DDR5
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For the majority of desktop users the most technically accurate answer is "no", they'd get more performance with 16GB of DDR5, but realistically they're not going to notice while browsing the web or typing in MS Office, so I'd always advise the higher capacity even though it's slower, for the reason that slightly faster memory performance is not noticeable, but running out of memory IS noticeable.

For games, the story is the same. For the majority of users, they'll get more performance with 16GB of DDR5, but as with desktop use, they're unlikely to notice (except perhaps for competitive gaming @ 1080p), so I'd still suggest they take 32GB of DDR4 over 16GB of DDR5.

If you're interested in this question because you're considering a platform upgrade soon, then I'd save your money, because 16GB is still enough to last you a year or two until the overhaul.

DAS said:
If I added my existing 16GB to the new 16GB, would I see better overall performance from 32GB of mixed RAM compared to just the new 16GB matched pair.
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Mismatched RAM has no impact on performance whatsoever. But, mismatched RAM can have/cause stability problems that mean you need it to run it more slowly and that has an indirect impact on performance. For example: if you have a Ryzen CPU and it can run 2 sticks at 3200, or 4 sticks only work at defaults (e.g. 2133), you'd be better off (and this likely to be noticeable) with the 2 sticks in the vast majority of games.
 
If you added two different RAM modules together and the RAM no longer ran in dual channel mode, you'd lose performance.

Also, if your system can't run the one kit at CL latency of X (say CL16) and has to run it at a higher latency (such as CL19) to maintain stablility, you'd lose performance, especially when the system can only run the memory at a lower JDEC speed and higher latency settings.

Speed X number of channels x latency = more or less performance depending on variables. (4 sticks of DDR4 running at 2666 MT/s by CL19 will be slower than 2 sticks of RAM runnin at 3600 MT/s by CL16)

also also, it depends on the thing that you are doing. There are games out there that are very memory sensitive and faster with lower latency is better but again, there are games out there that do not care at all with regards to speed and latency and just prefer more RAM.

OP, I run 24gigs of RAM in my laptop in dual channel at 2T command rate and horrendouse clocks but I need the extra capacity as I often run a VMware image with 30 tabs open and listening to music and antivirus and NordVPN etc whilst doing no gaming so I don't care if it's technically slower, I just need the extra capacity as that has a bigger impact on performance.
 
For the sake of simplicity Capacity ( Size ) and Performance ( Speed ) are 2 totally seperate things.

Capacity - 8GB of RAM X will perform exactly the same as 64GB of RAM X

The only time you benefit from higher capacity of RAM is when you are using it all already/bottlenecked.
 
Capacity - 8GB of RAM X will perform exactly the same as 64GB of RAM X
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Well no, not necessarily, you get better performance with dual rank kits which is another variable with RAM.

I have a pair of dual rank 3200MT/s CL17 32gig (16gig by 2) which is faster than my 3600 MT/s CL14 kit (2 by 8gig).

You could also have worse performance with 64gigs of RAM if the memory controller on the CPU can’t handle the amount of RAM.

RAM is so incredibly complicated due to the number of variables and I’d highly recommend watching Buildzoids videos on RAM to gain a better understanding.

He goes into extreme depth on the subject.
 
JollyJamma said:
Well no, not necessarily, you get better performance with dual rank kits which is another variable with RAM.

I have a pair of dual rank 3200MT/s CL17 32gig (16gig by 2) which is faster than my 3600 MT/s CL14 kit (2 by 8gig).

You could also have worse performance with 64gigs of RAM if the memory controller on the CPU can’t handle the amount of RAM.

RAM is so incredibly complicated due to the number of variables and I’d highly recommend watching Buildzoids videos on RAM to gain a better understanding.

He goes into extreme depth on the subject.
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I'm fully aware of the depth of RAM variables - I did preface my post with ' For the sake of simplicity '.
 
I think its been covered but if whatever your running is needing say ~24GB of ram then running unmatched 16GB pairs (32GB) is going to be better than running a single (super fast) 16GB stick as your system would end up paging out the RAM.

But for most scenarios having an identical pair of DIMMs so they run properly in duel channel mode with identical timings is going to yield better results.
 
Thanks to everyone for their very helpful replies. It's clear now that I am going to get 2 new 8GB sticks. Whether I go for DDR4 or DDR5 depends on the costs and specs of the other components in the upgrade.

David
 
DAS said:
Thanks to everyone for their very helpful replies. It's clear now that I am going to get 2 new 8GB sticks. Whether I go for DDR4 or DDR5 depends on the costs and specs of the other components in the upgrade.

David
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Well don’t get 8gig DDR5 sticks, that takes away a lot of the performance advantages of DDR5.

Rather get 16gig DDR5 DIMMS. There’s a thread highlighting which RAM to buy that I posted recently, watch that.
 
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JollyJamma said:
Well don’t get 8gig DDR5 sticks, that takes away a lot of the performance advantages of DDR5.
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Not that I'd buy 8GB of DDR5, but have you seen some new benchmarks? From what I've seen so far, 8GB DDR4 (16Gbit) loses much more performance than 8GB DDR5 does :o
 
Tetras said:
Not that I'd buy 8GB of DDR5, but have you seen some new benchmarks? From what I've seen so far, 8GB DDR4 (16Gbit) loses much more performance than 8GB DDR5 does :o
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I had a listen to a few of Buildzoids videos and one of his videos specifically highlighted why he doesn’t do buying guides for 8gig DDR5 modules.

As far as I recall, using 8gig DDR5 modules basically reduces the bandwidth as the rank is halved (I will look into specifics but Buildzoid doesn’t exactly make the points in his videos easily to archive and recall).

DDR5 basically relies on huge memory bandwidth to deliver performing benefits over DDR4.

That being said, Would I buy 8gig DDR5 RAM modules and accept the loss in performance to ensure that I could buy better RAM in the future when I had more money because the motherboard was more expensive? Absolutely.
 
JollyJamma said:
As far as I recall, using 8gig DDR5 modules basically reduces the bandwidth as the rank is halved (I will look into specifics but Buildzoid doesn’t exactly make the points in his videos easily to archive and recall).

DDR5 basically relies on huge memory bandwidth to deliver performing benefits over DDR4.

That being said, Would I buy 8gig DDR5 RAM modules and accept the loss in performance to ensure that I could buy better RAM in the future when I had more money because the motherboard was more expensive? Absolutely.
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I know that theoretically 8GB DDR5 is supposed to be bad, but I'm only referring to the benchmarks I've seen that do the comparison and from what I've seen, DDR4 can lose A LOT of performance with 16Gbit modules (like up to 20 odd percent), but 8GB DDR5 only lost a few. I don't know if that's a result which is valid for the longer-term or not (e.g. if it would apply equally to a game like Starfield which seems to be memory sensitive).
 
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