B650 AM5 - PCIe 4.0 ONLY mbo appears?

[chrcoluk]

Imagine only needing Gen5 4x for a 4090. Wouldn't that be nice . It basically which came first, chicken or the egg. I see a bright further for Gen5, just takes people to stop saying it useless. 4x could go to the GPU and the rest can be used for more USB4 and extra PCIE slots.

They can already add more PCIE slots than they already do but seems now most boards are limited. The lack of PCIE slots I think isnt due to bandwidth but rather a design choice to cater for heavy M.2 users which the slots take up valuable board real estate.

In years gone by the chipset bandwidth was much more limited than it is now and it was common place to have 3-5 slots on a board with price at 1/4 of what it is now. The motherboard industry feels like its almost as bad as GPUs in terms of value for money.

The problem for one is PCIE5 seems to need more layers on the board, which adds a lot of $$ to the price point for no practical gain (just spec ego).

The solution is either m.2 slots at back of board or replacing at least 2 of the slots with addon card that has its own m.2 slots. However I am not convinced the board vendors see this as a problem to fix, as removing the PCIE slots conveniently seg's the market so if you want to add lots of i/o capacity e.g. you now more likely need to go out and buy a server board or HEDT if it gets revived, plus in addition the review industry keeps patting them on the back for their current strategy.

 

[Calenhad]

The problem for one is PCIE5 seems to need more layers on the board, which adds a lot of $$ to the price point for no practical gain (just spec ego).

It is not really about more layers. It is the quality of the signal. Which usually means shorter traces between cpu and m.2 socket compared to pcie 4.0 m.2. So a cheaper motherboard is less likely to have the necessary build quality.
Having the slot on the backside of the motherboard is one way to get shorter traces, but it is also a good method for cooking a pcie 5.0 ssd. They get hot with decent airflow. I would not want to stick one on the back of my motherboard

 

[AusWolf]

Got it, meant to be the NVME slot only

PCI-E 5.0 is not mentioned anywhere in the user manual, so either this board doesnt support it as a unique 'feature' or we're about to see regular B650's lack 5.0

My MSi Pro B650M-A WiFi doesn't have any 5.0.

your own link mentions exactly what OP is asking. Why is there no PCIe 5.0 M.2 NVME slot when there is supposed to be at least one for all of them as mandated by AMD.

It's not mandated.

It is not really about more layers. It is the quality of the signal. Which usually means shorter traces between cpu and m.2 socket compared to pcie 4.0 m.2. So a cheaper motherboard is less likely to have the necessary build quality.
Having the slot on the backside of the motherboard is one way to get shorter traces, but it is also a good method for cooking a pcie 5.0 ssd. They get hot with decent airflow. I would not want to stick one on the back of my motherboard

Not to mention swapping the drive, which could be a nightmare depending on your chassis.

 

[chrcoluk]

It is not really about more layers. It is the quality of the signal. Which usually means shorter traces between cpu and m.2 socket compared to pcie 4.0 m.2. So a cheaper motherboard is less likely to have the necessary build quality.
Having the slot on the backside of the motherboard is one way to get shorter traces, but it is also a good method for cooking a pcie 5.0 ssd. They get hot with decent airflow. I would not want to stick one on the back of my motherboard

Well I guess buildzoid is wrong then?

Its only very recently he explained things in a video, with boards that have 5.0 slots at the bottom, and the reason these boards been more expensive been the extra quality required required (Which includes more layers).

Build a gen 3 only board and you can get away with less layers.

In short gen 5 PCIE means more $$ for something that is useful for benchmarks.

 

[LuxZg]

My MSi Pro B650M-A WiFi doesn't have any 5.0.


It's not mandated.

You're right about your board, so there's at least two models from different manufacturers.

But I'm not sure about mandated or not. Picture from official AMD presentation has "*" by X670 that points to 5.0 on x16 being optional. But B650 clearly says 5.0 M.2, no asterisk.

And I've seen no official talk about it being optional, nor any news site reporting it.

I'm not against it, though, if they added "E" for 5.0 x16 they could've added some letter or different number for "4.0 - only". After all, name of the boards aren't about chipset, but wiring, so they could call these B640 or whatever. Not to say A620...

 

[Dr. Dro]

your own link mentions exactly what OP is asking. Why is there no PCIe 5.0 M.2 NVME slot when there is supposed to be at least one for all of them as mandated by AMD.

I think you misunderstood the chart, all tiers support at least one 5.0 M.2 slot but its implementation is mandatory only on X670E, highly encouraged on B650E and optional on X670 and B650

 

[Hofnaerrchen]

your own link mentions exactly what OP is asking. Why is there no PCIe 5.0 M.2 NVME slot when there is supposed to be at least one for all of them as mandated by AMD.

PCIe 5.0 (GPU OR NVME) is only madatory for "E" class chipsets. For everything else (670/650 NON-E) PCIe 4.0 is OK.

 

[AusWolf]

You're right about your board, so there's at least two models from different manufacturers.

But I'm not sure about mandated or not. Picture from official AMD presentation has "*" by X670 that points to 5.0 on x16 being optional. But B650 clearly says 5.0 M.2, no asterisk.

And I've seen no official talk about it being optional, nor any news site reporting it.

I'm not against it, though, if they added "E" for 5.0 x16 they could've added some letter or different number for "4.0 - only". After all, name of the boards aren't about chipset, but wiring, so they could call these B640 or whatever. Not to say A620...

Yeah, the presentation said 5.0, but it didn't say whether it comes with it, or if it's optional. Oh, the joys of marketing!

 

[Mussels]

AMD say the chipset supports it

The board makers can cut corners and not add it/enable it to save costs, and have begun doing so it seems