Question AMD B650e and b670e chipsets: some questions

[80251]

What is the difference between the B650e and B670e chipsets? My google-fu came up w/the only difference being the number of PCIe lanes.

Back in the z390 days, I was told it's best to get a motherboard w/only two DIMM slots because then it was easier to overclock the memory, is this true now or true of B650e and B670e chipsets?

Is either chipset more conducive to memory and core overclocking than the other?

 

[Lutfij]

Back in the z390 days, I was told it's best to get a motherboard w/only two DIMM slots because then it was easier to overclock the memory, is this true now or true of B650e and B670e chipsets?
If you work with two sticks of ram, you place less stress on the memory controller. This holds true for platforms dating as far back as 2 decades ago.

You sure you've got the chipset models down right? I don't see a B670E chipset, with or without Google searches.

What are you looking for out of your foray into an AMD AM5 platform? Depending on that answer, you'll be directed to the right chipset/motherboard for your needs.

 

[CountMike]

What is the difference between the B650e and B670e chipsets? My google-fu came up w/the only difference being the number of PCIe lanes.

Back in the z390 days, I was told it's best to get a motherboard w/only two DIMM slots because then it was easier to overclock the memory, is this true now or true of B650e and B670e chipsets?

Is either chipset more conducive to memory and core overclocking than the other?

There are no B670 just X670 chipsets. Difference between X670 and B650 or A620 is between capabilities of chipsets not in motherboards themselves and number of RAM slots depends on MB size, chipset has nothing to do with RAM.
X650 MBs have more and higher version of PCIe lanes connected to it, Fastest lanes are those connected to CPU.
There are also X870 chipsets and coming soon B850 with even more capabilities, with all PCIe v5.0 and USB4 and thunderbolt controllers etc.
They are all compatible with all 7000 series Ryzen and with new BIOS version, 8000 and 9000(x3D).
8000G and 9000 CPUs can also use faster RAM and are compatible with using all 4 memory channels without overloading IMC controller. actually that started with 5000 series up to a point.

 

[80251]

@CountMike
So if I want a 9800x3D build I should wait for the x870 chipset motherboards to become available? Pcpartpicker doesn't list any 870 motherboards as being available. It does list 880G, 880GX, 890FX and 890GX. Are those older or newer chipsets? Does the x870 chipset support CUDIMMs?
I used to only buy AMD because I couldn't afford Intel, but that was way back in the Athlon days (when Nvidia still made some excellent chipsets for AMD CPUs).

 

[CountMike]

@CountMike
So if I want a 9800x3D build I should wait for the x870 chipset motherboards to become available? Pcpartpicker doesn't list any 870 motherboards as being available. It does list 880G, 880GX, 890FX and 890GX. Are those older or newer chipsets? Does the x870 chipset support CUDIMMs?
I used to only buy AMD because I couldn't afford Intel, but that was way back in the Athlon days (when Nvidia still made some excellent chipsets for AMD CPUs).

X870 MBs are available for sale although may not be at your location. Those other ones you mention are not for AMD Ryzen CPUs but for much older and out of production FX lineup. Any MB with DDR5 should support CUDIMMs although that depends on BIOS and only Ryzen 8000 and 9000 series CPUs. can use it. CUDIMMs shouldn't be consideration unless building maximum system.
Forget about comparing those older systems, except for initials "PC", it's whole new ballpark.

 

[80251]

Thanks CountMike. Are there any advantages to an x870 MB over the B650e and x670e chipsets? Maybe better overclocking capabilities for RAM and CPU?
It also doesn't look like there are any 2 DIMM B650e or x670e chipset motherboards for sale (at least on pcpartpicker). Would a 2 DIMM motherboard get you noticeably higher RAM overclocking headroom?

 

[Eximo]

Are there any advantages to an x870 MB over the B650e and x670e chipsets? Maybe better overclocking capabilities for RAM and CPU?
It also doesn't look like there are any 2 DIMM B650e or x670e chipset motherboards for sale (at least on pcpartpicker). Would a 2 DIMM motherboard get you noticeably higher RAM overclocking headroom?

Not sure there is much in the way of overclocking needed. I think the CPU is going to limit you more than the motherboard.

Theoretically, yes, a 2 slot board will perform a little better when it comes to overclocking memory. But the getting Ryzen to go fast has been a challenge. Usual recommendation is to stop at 6400 for best results, and you can just buy that. So other than tweaking the sub timings as low as they will go, not a lot to do there.

 

[CountMike]

Om the MB, 2 or 4 slots doesn't matter if you use only one or 2. Under certain conditions even maxing RAM capacity is not a problem with latest generations of processors.
MB has nothing to do with that, memory controller is in CPU, not on MB and that's possible limiting factor.
1. low to medium frequency. not over IMC's max, no overclock frequency-
2. Single or dual rank memory.
The problem ? Overloading IMC which necessitates higher voltages and can cause instability because of IMC's overload and higher temperature.
DDR5 has double the bandwidth of DDR4 so memory "speed" so it's not as important or critical for overall performance. So, if you need large amount of memory, that should be given higher consideration over "speed",
I'm putting "Speed" under quotes because it's combination of frequency, latency and single/dual channel .
That's why memory performance is now stated as
MT/s = (Megatransfers per second), used to measure the effective data rate of RAM instead of just frequency in MHz.
As an example, ,y RAM is running at 6200MHz @Cl30 which gives me 6400MT/s real speed. Actual RAM frequency is 3100MHz but because it's DDR (Double Data Rate) it's multiplied by two.

 

[80251]

@CountMike I had thought that when you had more than one DPC it meant the bus design became more complicated in that it either became a daisy chain or t-junction model and there were advantages/disadvantages associate w/both?

 

[Eximo]

That is basically the idea. And if you look at the enthusiast overclocker class boards, they have the Daisy Chain configuration and only two slots. T-Topology generally has better results than Daisy Chain when all four slots are populated, but can't go as fast when only two sticks are used. But a board with Daisy Chain and 4 slots occupied has more physical latency and can make very high memory frequencies not work either.

That was more DDR4 related information.

Not sure how it relates to the 2x32 bit configurations of DDR5 let alone CUDIMMS.

Haven't done a deep dive on learning about DDR5 just yet. I don't have any DDR5 systems.

 

[CountMike]

@CountMike I had thought that when you had more than one DPC it meant the bus design became more complicated in that it either became a daisy chain or t-junction model and there were advantages/disadvantages associate w/both?

With 2 slots. architecture/design is same as with 4 except one channel is omitted. No slots and no traces and not connected to one IMC channel. If you don't install additional RAM nothing is connected, It's like not closing battery>light-bulb circuit. Simple as that.

 

[Eximo]

With 2 slots. architecture/design is same as with 4 except one channel is omitted. No slots and no traces and not connected to one IMC channel. If you don't install additional RAM nothing is connected, It's like not closing battery>light-bulb circuit. Simple as that.

If I took the time I could find all the enthusiast overclockers who say otherwise. But these are the people that are going for the absolute extremes. At more sane speeds it probably doesn't make that much of a difference.