Question 2 rams with different speeds

Jun 25, 2019
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So on my original setup i had 2x 8gb 2400 ram. I got for a present 1 more ram, but it is 16gb 3200. I have 2 slots. So i wonder can i somehow have 24gb ram ? And how to lower speed from newer one? I Have too boot Pc only with him, and to change speed manually? I tried to just insert new ram with old one but only thing i got is black screen
 

Schlachtwolf

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Jun 22, 2019
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No, 2 different speeds will not be the issue as the faster stick would automatically only be able to go as fast as the slower stick. But it will not work as the sticks are different capacity, and more than likely different models so are not compatible.

The reason RAM is sold in kits is they are guaranteed to work together, sticks from the same maker, same speed, same GB size but from a seperate silicon batch may not work with each other. RAM is best bought as a kit and what you have will not work no matter what you do.

Sorry to bear such bad news,....

Cheers
 
Reactions: mctrader07
Jun 25, 2019
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10
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No, 2 different speeds will not be the issue as the faster stick would automatically only be able to go as fast as the slower stick. But it will not work as the sticks are different capacity, and more than likely different models so are not compatible.

The reason RAM is sold in kits is they are guaranteed to work together, sticks from the same maker, same speed, same GB size but from a seperate silicon batch may not work with each other. RAM is best bought as a kit and what you have will not work no matter what you do.

Sorry to bear such bad news,....

Cheers
Thank you for response. I got it as a gift so probably i will sell them to buy something esle. Just, what is better to have 2x8gb 2400 or 1x16 3200. What is better solution, what will rin faster
 
Jun 25, 2019
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What CPU and motherboard do you have, if intel then 2x8gb @ 2600 is fine but a Ryzen likes fast Ram so 2x8gb @ 3200, this is very basic info unless I know what xactly you have :)
I have ryzen 7 2700x with msi b450m pro m2 max. Maybe i put it wrong. I have 2x8gb 2400 and 1x16gb 3200. Im wondering should i stay on dual ram, or to switch to single because of that 800mhz difference.
 
You plan might have worked with intel, but hot with ryzen.
Ryzen requires symmetrical ram.
Ryzen performance is closely tied to ram.
The speeds you see 2400 or 3200 assume two sticks operating in dual channel mode.
Your option of 1 x 3200 would actually be slower since it would be effectively 1600 speed.
Your 2 x 2400 option would be better.
 
Reactions: mctrader07

Darkbreeze

Titan
Moderator
You plan might have worked with intel, but hot with ryzen.
Ryzen requires symmetrical ram.
Ryzen performance is closely tied to ram.
The speeds you see 2400 or 3200 assume two sticks operating in dual channel mode.
Your option of 1 x 3200 would actually be slower since it would be effectively 1600 speed.
Your 2 x 2400 option would be better.
Sorry Geofelt, but this is wrong.

The double DATA RATE of DDR memory has nothing at all to do with dual channel operation that doubles the BANDWIDTH. Bandwidth and data rate are completely different things. A single stick of 3200mhz memory still runs at 3200mhz, not 1600mhz. What it LOSES by not being paired with another DIMM is the doubling of the bandwidth. It is still a hit to performance, but it is NOWHERE near as dramatic as it would be if it were a halving of the data rate/frequency.

DDR should not be confused with dual channel, in which each memory channel accesses two RAM modules simultaneously. The two technologies are independent of each other and many motherboards use both, by using DDR memory in a dual channel configuration.
 

Darkbreeze

Titan
Moderator
No, 2 different speeds will not be the issue as the faster stick would automatically only be able to go as fast as the slower stick. But it will not work as the sticks are different capacity, and more than likely different models so are not compatible.

The reason RAM is sold in kits is they are guaranteed to work together, sticks from the same maker, same speed, same GB size but from a seperate silicon batch may not work with each other. RAM is best bought as a kit and what you have will not work no matter what you do.

Sorry to bear such bad news,....

Cheers
This is wrong too. Memory modules with different amounts can, and are (All the time), used. You will sometimes lose dual channel operation (Not to be confused with double data rate, wink, wink) but unless the memory is unsupported by the motherboard because of a configuration problem such as too many ranks, speed beyond what is supported (And even that will usually just downclock in order to be compatible) or is simply too different from the existing memory to want to "play nice", there is no reason you can't add a DIMM that is a different amount than the rest of your memory.

In most cases this will result in some form of "flex mode", even on AMD platforms, where your two matched sticks that are installed in the second and fourth DIMM slots (Over from the CPU going towards the edge of the motherboard. So, 4th slot is closest to the edge. A2 and B2 for most boards, DDR4_1 and DDR4_2 for some boards, but always the second and fourth slots) run in dual channel but the oddball DIMM runs in single channel. It is also possible to have two different sized DIMMs in the A2 and B2 slots and have them run ONLY A PORTION of the memory in dual channel.

So for those configurations, something like a 4GB and 8GB DIMM used together in the A2 and B2 slots COULD result in 8GB of memory (4GB from each slot) running in dual channel and another 4GB running in only single channel.

Regardless of dual channel considerations, as long as the memory is similar enough to play nice, it doesn't matter that they are different capacities.

Short version, you MIGHT be able to get that 16GB DIMM to work with your existing memory, and you might not. It really depends on the quality of the motherboard and whether the three DIMMS want to play nice together or not. It also matters whether your chipset supports 16GB DIMMs, at all.
 
@Darkbreeze, I stand corrected on the difference between data rate and bandwidth.

I was not aware that ryzen supported different sized modules; I thought they needed to be symmetrical.
In the case of Intel, I know that it supports flex mode where the matched capacity on each channel will operate in dual channel mode and the odd capacity will operate in single channel mode.
Again, assuming the disparate sticks play nice enough to run at all.
 

Darkbreeze

Titan
Moderator
They always have on pre-Ryzen, for as long as there has been such a thing that I can remember, but apparently, on Ryzen they do as well. I cannot say for absolute certain this is correct because I have not tried to use an asymmetrical memory configuration on a Ryzen platform myself, but I will the next time I work on one.

AMD Ryzen asymmetrical memory configurations

Jim, Tradesman1, seemed to think that AMD did (And they DID) as far back as AT LEAST 2015, and more like 2006 at least, for sure, because I've used it on platforms back then such as AM3 and AM3+.

 
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