Which Is Better For 3600mhz CL18 8x4 32GB Or 16x4 64GB

[kzymon]

I Want To Upgrade My Ram, Which Is Faster? 8x4 32GB Or 16x4 64GB The Ram Is 3600MHZ CL18

[RONOTHAN##]

What kits are you comparing, and do you need the 64GB of RAM? If you need 64GB of RAM, you're better off going 2x32GB, it's probably cheaper and has a better chance of working. 16x4, depending on the exact kit you have and what CPU you're using (all of this is assuming you're using one of the consumer platforms, not X299 or Threadripper), can put a ton of load on the memory controller and cause you to have a hard time hitting XMP speeds if the kits are dual rank. If you get single rank, then it's gonna be fine. It's about 50/50 whether you get dual rank kits or single rank kits when buying 16GB sticks. 

[mariushm]

Your motherboard is most likely dual channel, which means there's  two channels of memory, and each channel can have one or two sticks - the sticks on one channel are seen by the cpu as a single big stick of memory.

Dual channel means the processor can read or write data from both memory channels in parallel, so it can read or write something twice as fast.

 

When you use 4 memory sticks, there's more power going to the memory slots and there's more signals between the ram slots and the cpu, so it's a tiny bit harder for the cpu to work with four memory sticks and if the motherboard is cheap, it's possible the signal quality decreases just enough to have to configure the memory at lower frequencies in order to get it working. So for example, on some cheap motherboard you could have 2 memory sticks running at 3600 Mhz, but with 4 sticks of the same memory you may need to lower the frequency to 3200 Mhz or 3000 Mhz to get the four sticks working.

 

There's also another small detail ... there's SR and DR memory sticks, Single Rank or Dual Rank - it has to do with how the memory chips are arranged on the memory stick and how they can be accessed by the CPU.

A dual rank stick has two groups of memory chips, and basically the memory controller can access those two groups independently. This allows the memory controller to send commands and get one group of chips ready to receive or transmit data, while it's reading data from the other group of memory chips and as soon as it's done it can switch to reading data from the other group of memory chips.

Imagine it like this: let's say it takes 10 seconds to find some data in ram, and then it takes 50 seconds to read the data (very inflated numbers to make it obvious).

While the cpu is reading another picture from the first group of chips, it can tell the other group "get ready to fetch the picture" and instead of just waiting until those 10 seconds pass, it can continue reading the previous picture from the first group of chips. The second group will eventually be ready and just wait until the CPU starts fetching that picture.

 

So Dual Rank memory sticks can give you a tiny performance boost, versus Single Rank memory sticks but of course there's tradeoffs... because there's more memory chips on a dual rank stick and it's more complex to communicate with 2 groups of memory chips, again it's harder for the CPU to work with some memory sticks at very high frequencies.

 

Because of this, most overclockers prefer single rank memory sticks, simpler communication and less noisy signals (because less chips on stick) means the stick can be overclocked to higher frequencies before the signal becomes too bad to be understood by the cpu.

 

8GB DDR4 sticks will now be mostly Single Rank, because most ram chip manufacturers no longer produce 512 MB chips to make a single 8 GB stick out of 16x512 memory chips. So if you use 2 sticks or 4 sticks,  it will the same performance.

16 GB of memory will be most likely Dual Rank, using 16 x 1 GB memory chips arranged in 2 groups of 8 chips.

So even 2 x 16 GB should be a tiny bit better than 4 x 8 GB  because of Dual Rank.

 

4 x 16 GB will probably not be worth it, unless you often use applications that consume more than 16 GB.  And as I explained above, you risk having to reduce the frequency from 3600 Mhz to 3200 Mhz,  because working with 4 Dual Rank sticks is more difficult, harder for the motherboard and the processor.

 

 

[kzymon]

9 minutes ago, mariushm said:

Your motherboard is most likely dual channel, which means there's  two channels of memory, and each channel can have one or two sticks - the sticks on one channel are seen by the cpu as a single big stick of memory.

Dual channel means the processor can read or write data from both memory channels in parallel, so it can read or write something twice as fast.

 

When you use 4 memory sticks, there's more power going to the memory slots and there's more signals between the ram slots and the cpu, so it's a tiny bit harder for the cpu to work with four memory sticks and if the motherboard is cheap, it's possible the signal quality decreases just enough to have to configure the memory at lower frequencies in order to get it working. So for example, on some cheap motherboard you could have 2 memory sticks running at 3600 Mhz, but with 4 sticks of the same memory you may need to lower the frequency to 3200 Mhz or 3000 Mhz to get the four sticks working.

 

There's also another small detail ... there's SR and DR memory sticks, Single Rank or Dual Rank - it has to do with how the memory chips are arranged on the memory stick and how they can be accessed by the CPU.

A dual rank stick has two groups of memory chips, and basically the memory controller can access those two groups independently. This allows the memory controller to send commands and get one group of chips ready to receive or transmit data, while it's reading data from the other group of memory chips and as soon as it's done it can switch to reading data from the other group of memory chips.

Imagine it like this: let's say it takes 10 seconds to find some data in ram, and then it takes 50 seconds to read the data (very inflated numbers to make it obvious).

While the cpu is reading another picture from the first group of chips, it can tell the other group "get ready to fetch the picture" and instead of just waiting until those 10 seconds pass, it can continue reading the previous picture from the first group of chips. The second group will eventually be ready and just wait until the CPU starts fetching that picture.

 

So Dual Rank memory sticks can give you a tiny performance boost, versus Single Rank memory sticks but of course there's tradeoffs... because there's more memory chips on a dual rank stick and it's more complex to communicate with 2 groups of memory chips, again it's harder for the CPU to work with some memory sticks at very high frequencies.

 

Because of this, most overclockers prefer single rank memory sticks, simpler communication and less noisy signals (because less chips on stick) means the stick can be overclocked to higher frequencies before the signal becomes too bad to be understood by the cpu.

 

8GB DDR4 sticks will now be mostly Single Rank, because most ram chip manufacturers no longer produce 512 MB chips to make a single 8 GB stick out of 16x512 memory chips. So if you use 2 sticks or 4 sticks,  it will the same performance.

16 GB of memory will be most likely Dual Rank, using 16 x 1 GB memory chips arranged in 2 groups of 8 chips.

So even 2 x 16 GB should be a tiny bit better than 4 x 8 GB  because of Dual Rank.

 

4 x 16 GB will probably not be worth it, unless you often use applications that consume more than 16 GB.  And as I explained above, you risk having to reduce the frequency from 3600 Mhz to 3200 Mhz,  because working with 4 Dual Rank sticks is more difficult, harder for the motherboard and the processor.

 

 

My Motherboard Is Gigabyte B450M DS3H V2

[kzymon]

1 hour ago, RONOTHAN## said:

What kits are you comparing, and do you need the 64GB of RAM? If you need 64GB of RAM, you're better off going 2x32GB, it's probably cheaper and has a better chance of working. 16x4, depending on the exact kit you have and what CPU you're using (all of this is assuming you're using one of the consumer platforms, not X299 or Threadripper), can put a ton of load on the memory controller and cause you to have a hard time hitting XMP speeds if the kits are dual rank. If you get single rank, then it's gonna be fine. It's about 50/50 whether you get dual rank kits or single rank kits when buying 16GB sticks. 

My Motherboard Is Gigabyte B450M DS3H V2 And My CPU Is Ryzen 3 3200g

[RONOTHAN##]

3 minutes ago, kzymon said:

My Motherboard Is Gigabyte B450M DS3H V2 And My CPU Is Ryzen 3 3200g

Your CPU is Zen+, so very weak memory controller. Getting 3200MHz running is 50/50 for if it will work, let alone 3600MHz. You're not gonna be able to get 3600MHz to work without a ton of effort, and getting 3600MHz to work with 64GB of RAM is even more work. 

 

Basically, save money and go 3200MHz. You still might not be able to run that (again, very weak memory controller, and 4 sticks puts a lot of strain on the controller), but it's about as cheap as you can get. Plus, outside of a select few workloads, you're probably better off buying a better CPU and a lower capacity kit than buying a super high capacity kit and dealing with that CPU. What are you actually doing with the system that you want 32GB+ of RAM?

[kzymon]

1 hour ago, RONOTHAN## said:

Your CPU is Zen+, so very weak memory controller. Getting 3200MHz running is 50/50 for if it will work, let alone 3600MHz. You're not gonna be able to get 3600MHz to work without a ton of effort, and getting 3600MHz to work with 64GB of RAM is even more work. 

 

Basically, save money and go 3200MHz. You still might not be able to run that (again, very weak memory controller, and 4 sticks puts a lot of strain on the controller), but it's about as cheap as you can get. Plus, outside of a select few workloads, you're probably better off buying a better CPU and a lower capacity kit than buying a super high capacity kit and dealing with that CPU. What are you actually doing with the system that you want 32GB+ of RAM?

Will It Work With 8x2 Only?

[mariushm]

It will work with 2 sticks, with 4 sticks, will work with 8 GB or 16 GB sticks ..

 

It's just that you're not guaranteed you'd be able to keep the 4 sticks at 3600 Mhz,  you may have to go in BIOS and set them at 3200 Mhz or 3000 Mhz.

 

The first Ryzen generations were more "picky" about memory chips, they favored memory chips from some manufacturers and were less optimized for other memory chips. So you could get 3200 Mhz or 3600 Mhz with some sticks, but you could not get that with memory sticks made with other chips.

 

There were multiple BIOS updated that updated the microcode inside the processor and increased compatibility with various memory chips, improving things. Still, it's only so much you can improve with software (microcode inside the CPU)... later Zen versions improved the memory controller at a hardware level.

 

My advice would be to get 2 x 16 GB sticks if you want 32 GB of memory.  If you don't need 32 GB, get 2 sticks of 8 GB.  I'd aim for 3200 Mhz CL16 or CL18 ... CL16 would be better but it's not a big deal.

[RONOTHAN##]

4 minutes ago, kzymon said:

Will It Work With 8x2 Only?

3200MHz, probably. With 3600MHz, not without manually overclocking it. 

 

Though again, what kits are you trying to compare?

[SavageNeo]

more ram does not mean faster. with 3200g you dont need over 16gb of ram to anythign other than editing large vides.