2 vs 4 sticks (DDR5) of ram on 7800x3d

[Thehelloguy95]

I was planning on going with 4 sticks Kingston FURY Beast RGB DDR5 6000MHz 16GB with the 7800x3d, but I read mixed things about it all and unsure about it all...

Are there benefits with running with 4 sticks on the 7800x3d? Was planning on going with the ASUS ROG Crosshair X670E Extreme motherboard for my upgrade.

 

WILL GLADLY TAKE SUGGESTIONS FOR MEMORY STICKS AS WELL THAT WOULD GO WELL WITH THE MB!

[ZeusXI]

9 minutes ago, Thehelloguy95 said:

I was planning on going with 4 sticks Kingston FURY Beast RGB DDR5 6000MHz 16GB with the 7800x3d, but I read mixed things about it all and unsure about it all...

Are there benefits with running with 4 sticks on the 7800x3d? Was planning on going with the ASUS ROG Crosshair X670E Extreme motherboard for my upgrade.

 

WILL GLADLY TAKE SUGGESTIONS FOR MEMORY STICKS AS WELL THAT WOULD GO WELL WITH THE MB!

Just more bandwidth. I personally find 2 sticks more stable. 

[Deadpool2onBlu-Ray]

2

[Thehelloguy95]

4 minutes ago, ZeusXI said:

Just more bandwidth. I personally find 2 sticks more stable. 

Sounds kinda dumb, but what's the benefits with higher bandwidth?

[Aaron_T]

To a greater or lesser degree, historically more than a single DIMM per memory channel (IE 4 sticks instead of 2 in a consumer platform) has been done for two main reasons, more capacity and aesthetics.

In consumer applications, a single DIMM per memory channel (in your case, 2 sticks) is done when maximum performance and stability is your desired outcome, vs capacity/aesthetics.

[ZeusXI]

1 minute ago, Aaron_T said:

To a greater or lesser degree, historically more than a single DIMM per memory channel (IE 4 sticks instead of 2 in a consumer platform) has been done for two main reasons, more capacity and aesthetics.

In consumer applications, a single DIMM per memory channel (in your case, 2 sticks) is done when maximum performance and stability is your desired outcome, vs capacity/aesthetics.

I agree with this. You beat me to it ahah

[Eigenvektor]

5 minutes ago, Thehelloguy95 said:

Sounds kinda dumb, but what's the benefits with higher bandwidth?

Higher memory bandwidth = more performance in tasks that are bandwidth sensitive.

 

Games typically benefit more from lower latency.

[Thehelloguy95]

4 minutes ago, ZeusXI said:

I agree with this. You beat me to it ahah

I appreciate both your answers

[Thehelloguy95]

Just now, Eigenvektor said:

Higher memory bandwidth = more performance in tasks that are bandwidth sensitive.

 

Games typically benefit more from lower latency.

So basically 2 sticks over 4 then if I get ya there?

[ZeusXI]

4 minutes ago, Thehelloguy95 said:

So basically 2 sticks over 4 then if I get ya there?

Correct. 

[Darknighterror]

I'd like to add that there seem to be some serious issues with using 4 sticks DDR5 (not always, but I've seen enough post about it, that I personally would try to avoid it)

[Eigenvektor]

3 minutes ago, Thehelloguy95 said:

So basically 2 sticks over 4 then if I get ya there?

Yes, I'd recommend to go with two sticks unless you need a memory capacity that isn't reachable with only two.

 

When it comes to latency, it's not quite that simple. But generally two sticks is less work for the CPU's memory controller, so you're more likely to be able to run at full XMP speed or even add some additional overclock yourself. Overclock could be some combination of faster speed or lower latency.

[Aaron_T]

@Thehelloguy95 To clarify some of the above:

Multiple RAM DIMMs per memory channel does not increase memory bandwidth. Memory bandwidth is dictated by the type and number of memory channels that are supported by your CPU. So for example, in consumer platforms like Ryzen 7000 series, this is 2 memory channels. Meaning your max performance scenario is to have a single DIMM of the highest performance RAM that your CPU and motherboard support per memory channel.

The corollary to the above is that having more than 1 RAM DIMM per memory channel does in fact reduce your overall performance by increasing access latency. Additionally, and completely unrelated to theoretical maximum performance, DDR 5 RAM has had stability issues with more than 1 DIMM per channel since it's consumer debut. The stability issues are getting better, but still a gamble. 

[WereCat]

13 minutes ago, Aaron_T said:

@Thehelloguy95 To clarify some of the above:

Multiple RAM DIMMs per memory channel does not increase memory bandwidth. Memory bandwidth is dictated by the type and number of memory channels that are supported by your CPU. So for example, in consumer platforms like Ryzen 7000 series, this is 2 memory channels. Meaning your max performance scenario is to have a single DIMM of the highest performance RAM that your CPU and motherboard support per memory channel.

The corollary to the above is that having more than 1 RAM DIMM per memory channel does in fact reduce your overall performance by increasing access latency. Additionally, and completely unrelated to theoretical maximum performance, DDR 5 RAM has had stability issues with more than 1 DIMM per channel since it's consumer debut. The stability issues are getting better, but still a gamble. 

It increase bandwidth because you increase the amount of ranks... at the cost of some latency. Depending on the type of memory and application the trade off may be worth it.

I personally run Quad Rank of DDR4 (4x16GB Dual Rank sticks) and the latency penalty is somewhat diminished by the fact that Micron E-die has some hard limits that wouldn't allow me to tighten certain timings even if I only had 2 sticks. So I got a nice bandwidth increase at very minimal latency penalty which results in small performance boost.

 

Without manual memory tweaking though, you're likely to not benefit at all and also it's much more demanding on the memory controller. On Zen 5000series and lower you also have to keep FCLK with MEMCLK at 1:1 parity which also allows quad rank to be of bigger benefit since you can't just push RAM as high as you want.

This is not the case on 7000series where higher memory speeds are of greater benefit as you don't have to run it with sync with FCLK so you can likely squeeze way more performance out of 2 sticks rather than 4 as that would put just way too much strain on the memory controller.

 

And last thing:

 

4x single rank sticks should perform the same as 2x dual rank sticks (at least on DDR4, I don't really know much about DDR5 but I assume it still applies for the most part). So it was also a benefit to go with 2x Dual Rank as it was a performance boost due to having more ranks while still just 2 sticks.

[Aaron_T]

 

11 minutes ago, WereCat said:

It increase bandwidth because you increase the amount of ranks... at the cost of some latency. Depending on the type of memory and application the trade off may be worth it.

I personally run Quad Rank of DDR4 (4x16GB Dual Rank sticks) and the latency penalty is somewhat diminished by the fact that Micron E-die has some hard limits that wouldn't allow me to tighten certain timings even if I only had 2 sticks. So I got a nice bandwidth increase at very minimal latency penalty which results in small performance boost.

 

Without manual memory tweaking though, you're likely to not benefit at all and also it's much more demanding on the memory controller. On Zen 5000series and lower you also have to keep FCLK with MEMCLK at 1:1 parity which also allows quad rank to be of bigger benefit since you can't just push RAM as high as you want.

This is not the case on 7000series where higher memory speeds are of greater benefit as you don't have to run it with sync with FCLK so you can likely squeeze way more performance out of 2 sticks rather than 4 as that would put just way too much strain on the memory controller.

 

And last thing:

 

4x single rank sticks should perform the same as 2x dual rank sticks (at least on DDR4, I don't really know much about DDR5 but I assume it still applies for the most part). So it was also a benefit to go with 2x Dual Rank as it was a performance boost due to having more ranks while still just 2 sticks.

 

This is getting into semantics now.

Single VS Dual rank RAM does not change the available bandwidth of the memory channel, only how well the RAM DIMM and CPU memory controller are able to work together to saturate the memory channel. As I believe you said in other words, as MTU of the RAM increases, and timings of the RAM decrease and become tighter, the ranks of a DIMM become less important in general. So just another way to increase memory channel saturation.

But to be fair you're right about overall performance effects, in most situations outside of extreme overclocking, having dual rank RAM is an improvement in performance, well known for ddr4, and here is a reference for ddr5: https://www.anandtech.com/show/17269/ddr5-demystified-feat-samsung-ddr5-4800-ranks-dpcs-do-manufacturers-matter However, testing does still support the conclusion that a single DIMM per channel, of the highest performing RAM supported by your CPU and motherboard, will be the best case scenario for performance.

In this case though, a simple "Look for dual rank RAM, it's typically better performing per DIMM than single rank" would have sufficed, as I would expect all of this is quite confusing to the OP.

[Thehelloguy95]

2 hours ago, Darknighterror said:

I'd like to add that there seem to be some serious issues with using 4 sticks DDR5 (not always, but I've seen enough post about it, that I personally would try to avoid it)

Yeah, I seen and heard about it, but at the same time I seen people also being able to after some time when that memory training have kicked in a few times. If it all goes tits up, I just save the two extra sticks for a ITX build or something for lan'ing

[Thehelloguy95]

1 hour ago, Aaron_T said:

 

 

This is getting into semantics now.

Single VS Dual rank RAM does not change the available bandwidth of the memory channel, only how well the RAM DIMM and CPU memory controller are able to work together to saturate the memory channel. As I believe you said in other words, as MTU of the RAM increases, and timings of the RAM decrease and become tighter, the ranks of a DIMM become less important in general. So just another way to increase memory channel saturation.

But to be fair you're right about overall performance effects, in most situations outside of extreme overclocking, having dual rank RAM is an improvement in performance, well known for ddr4, and here is a reference for ddr5: https://www.anandtech.com/show/17269/ddr5-demystified-feat-samsung-ddr5-4800-ranks-dpcs-do-manufacturers-matter However, testing does still support the conclusion that a single DIMM per channel, of the highest performing RAM supported by your CPU and motherboard, will be the best case scenario for performance.

In this case though, a simple "Look for dual rank RAM, it's typically better performing per DIMM than single rank" would have sufficed, as I would expect all of this is quite confusing to the OP.

@Aaron_T I am all for learning and such! I admit I do want to run 4 stick mainly for looks, but I also want the ram since I been wanting to dab with video editing ngl (Something I forgot to add to the OG post ops x) But if I can get 4 sticks to run, only thing I could expect is a performance hit to a tiny degree?

 

If I only want performance,  it would be better to stick with 2 sticks of the ram I mentioned?

[Aaron_T]

@Thehelloguy95 I certainly get the desire for the 4 DIMM aesthetic! Perfectly reasonable, and I've done the same before. But it's good for you to know the trade offs.

The main issue with 4 DIMMs of DDR5 (at least right now) is that 4 DIMM kits of RAM from the manufacturer don't exist yet, at least not widely available, and it's always risky buying 2 kits of 2 DIMMs each, and expecting advertised speeds, like 6000mtu. Kits are manufacturer tested to work together at the advertised speeds, so getting 2 separate kits you may be fine and get the 6000mtu speed, or worst case you may end up having to run them all at 4800mtu (or the system just won't run with 4 DIMMs), but most likely it'll be somewhere in the middle like 5200 or 5600.

[Thehelloguy95]

1 hour ago, Aaron_T said:

@Thehelloguy95 I certainly get the desire for the 4 DIMM aesthetic! Perfectly reasonable, and I've done the same before. But it's good for you to know the trade offs.

The main issue with 4 DIMMs of DDR5 (at least right now) is that 4 DIMM kits of RAM from the manufacturer don't exist yet, at least not widely available, and it's always risky buying 2 kits of 2 DIMMs each, and expecting advertised speeds, like 6000mtu. Kits are manufacturer tested to work together at the advertised speeds, so getting 2 separate kits you may be fine and get the 6000mtu speed, or worst case you may end up having to run them all at 4800mtu (or the system just won't run with 4 DIMMs), but most likely it'll be somewhere in the middle like 5200 or 5600.

@Aaron_T Cheers! I keep this in mind! I LOVE the new DOMINATOR sticks thats coming out soon!