[SOLVED] M.2_2 slot if used downgrade pciex16 to x8 mode in Asus Rog strix b450-F

[Hardquery]

I m planning to purchase Ryzen 7 2700x and was selected motherboard and came across many minute differentiations In slots configurations which made complicated to select a motherboard.

As I am planning to build a pc for content creation. Video editing rendering and decided for Ryzen 7 2700x with two Samsung evo plus 970 or 980 Nvme m.2 500gb or 1tb drives and GPU 1650 super ddr6 6GB.

When I was selected mother boards I saw that due to sharing pcie lanes the in every motherboards for b450 x470 b550 or x570 m.2_2 second slot socket interface if I use the it disables pcie slots or sata ports or downgrade pcie slots.

In b450 only Asus Rog strix b450 F have both m.2_1 and m.2_3 with pcie 3x4 speed but it downgrades first primary pcie 3.0 16x16 mode to x8 mode . As it has 2 pcie 3.0 x16 slots 1st works In 16 lanes (x16)and second works in x8 ie.8 lanes mode. Now if I put graphic card on any slot it will work I. X8 mode will the GPU work fine in pcie 3x8 mode and what will it effect in rendering or video editing


I was finding motherboard with both m.2 slot either I pcie3.0x4 now many all b450 or x470 motherboards either locks pcie or sata ports if even m2 second slot is used .

In. B550 chipset boards all company MSI Asus gigabyte have m.2.1 slot of pcie 4x4 and m2_2 second slot one pcie 3x4.

In x570 Asus prime p have both been M2.2 slots working in pcie4x4 mode but there is no information of locking or degrading ports

Now my quotes are

1. Can we customize fro. Bios setting to which slot to degrade or lock in b450 or x470 boards if m.2 second slot is used

2.if primary pcie 3.0 x16 slot is degraded in x8 mode then what effect it makes to GPU aa there is no other slot


3. As in Asus prime x570 p have both m.2 slots pcie4x4 mode but first m.2_1 work from pcie3x4 a it works from CPU if Amd gen 2 or gen 1 is used . And works I. Pcie4x4 if gen 3 CPU is used as mentioned in the specification page...but there is no detail of pcie4x16 downgrading

4. there is no details I. X570 board of down grading or locking pcie in many boards or it lock I my sata ports...so where they share lanes in x570 doe in x570 boards it doesn't lock any pcie or it share fro. Sata ports it complicated and confusing

5. Is there any budgeted Gigabyte MSI Asus b450 or x470 motherboard which have both m.2 slot with pcie 3x4 mode and have two or three pcie 3x16 slots atleast. In first pcie 3.0x16 I can use GPU and second pcie3.0x16 can use m.2 or any other adapter cards both in pcie 3.0 X16 modes

6. Is there any budgeted economical b550 or x570 board within range of 200$ which have both m.2 works in pcie4x3 mode and have 2 to3 slots of pcie4x16 works in x16 mode and don't locks the primary and secondary slot.
. In first pcie 4.0x16 I can use GPU and second pcie4. 0x16 can use m.2 or any other adapter cards both in pcie4.0X16 modes

 

[rgd1101]

1)read the motherboard spec. not likely customize able
2)depend on the gpu. less performance
3)4)more pcie lane

 

[Math Geek]

in order to have more lanes than the cpu comes with, the motherboard has to have extra chips on it to support more lanes, and of course more lanes have to be put on the board itself. this is not cheap/budget/economical or anything else and is only available on those super expensive high end boards. in other words, it is not worth doing.

i'd suggest you stick with a b550/570 board with pcie 4.0. this way if your primary slot gets dropped to x8 it is still the same speed as 3.0x16. so really the same as a b450 board that stays at x16 mode.

that's probably the best you are going to do without spending $400 on the board. there is just only so many lanes to go around and too many devices that want to use them. you don't have to buy 4.0 nvme drives, in fact i recommend against them right now as they are not much faster than 3.0 drives and cost a lot more.

so stick to the pcie 4.0 boards, and know that even if it is x8 mode, it is still the same bandwidth as 16 pcie 3.0 lanes.

 

[getochkn]

More lanes comes down to needing threadripper if you want stuff maxxed. Otherwise you need to compromise and they all do it differently. I have a b550 steel legend board. It will do a 4.0 or 3.0 x4 nvme in the first slot with 6 sata ports, full pcie and 2.5gb ethernet. If I do a 2nd nvme, it runs at x2 instead of x4 and I loose 3 Sata ports but pcie stays the same. I have a 1tb nvme in the main drive that runs at 3000mbs. I have a wd.black at x2 that still runs at like 1800mbs.

 

[Hardquery]

@Math Geek bro first I thank you a lotz for giving your precious time precious advice opinions and thanks for sharing you knowledge and helping me clarify

[QUOTE="Math Geek, post: 22141912, member: 161950
i'd suggest you stick with a b550/570 board with pcie 4.0. this way if your primary slot gets dropped to x8 it is still the same speed as 3.0x16. so really the same as a b450 board that stays at x16 mode.
[/QUOTE]

@Math Geek bro thanks again. Yes I agree that the good options chips will not come in cheaper economical or. Budget and will and should be expensive and cost more. But nowadays aa compares to time of amd am3 athlon phenomenon or Intel's dual or quad core processor it was not so expensive as graphics chips was used to be inbuilt In motherboard chipset to,and now every small minute options like VRM capacior mosefets heatsinks even slots to cost double or 10 time higher. It's okay may be quality and time matters years technology may cost expensive now.

@Math Geek bro yes you told a good option to stuck for b550 or x570 which has pcie 4 x16 if it goes to x8 to it will give same speed as pcie 3x16 intelligent solution thanx grateful for solution advice and opinion

Just a small concern query if you can clear.my doubt..as I copied below in technical specification page of Asus x570 - P prime specifies that if we use Ryzen 5000 or 3000 series the pcie 4x16 and if we use Ryzen 4000G or 2000 series then it will give pcie3x16 and if we use 3000G or 2000G it will give pcie3.0x8 mode performance and if on amd x570 chipset it gives pcie4x4 mode...it means pcie 4 lanes depends on CPU processor not chipsets. as it clearly mentioned in it depends on cpu

Q1 does all x570 boards or b550 boards or only this Asus prime x570-P this specific model does use depends pcie slots lanes on the Processors CPU as it clearly mentions or may be hidden in others if yes then why the cost of chipsets they charge for motherboard. if I use Ryzen 7 2700x then it will give pcie 3x16 and I use 3700x the pcie 4x4

https://www.asus.com/Motherboards-Components/Motherboards/All-series/PRIME-X570-P/techspec

Expansion Slots
AMD Ryzen™ 5000 Series/ 3000 Series Desktop Processors
1 x PCIe 4.0 x16 (x16 mode)
AMD RyzenTM 4000 G-Series / 2000 Series Processors
1 x PCIe 3.0 x16 (x16 mode)
AMD RyzenTM 3000 G-Series / 2000 G-Series Processors
1 x PCIe 3.0 x16 (x8 mode)
AMD X570 chipset
1 x PCIe 4.0 x16 (max at x4 mode)
3 x PCIe 4.0 x1



Sameway, Just a small concern query if you can clear.my doubt..as I copied below in technical specification page of Asus x570 - P prime specifies that if we use Ryzen 5000 or 3000 series the M.2 _1 first slot pcie 4x4 and if we use Ryzen 4000G or 2000 or 3000G or 2000G series and on amd x570 chipset it M.2_2 second slot gives pcie4x4 mode...it means M.2 pcie 4 lanes depends on CPU processor not chipsets. as it clearly mentioned in it depends on cpu

Q2. does all x570 boards or b550 boards or only this Asus prime x570-P this specific model does use depends M.2 first pcie slots lanes on the Processors CPU as it clearly mentions or may be hidden in others if yes then why the cost of chipsets they charge for motherboard. if I use Ryzen 7 2700x then it will give M2.1 pcie 3x4 and I use 3700x the M.2 pcie 4x4.

Q3. The specification page does not specify that it degrade or disable any pcie or sata slot when using m.2_2 slot does x570 boards don't disable lock or degrade any slots as in many x570 specification page don't specifies info.

https://www.asus.com/Motherboards-Components/Motherboards/All-series/PRIME-X570-P/techspec

Storage
AMD Ryzen™ 5000 Series/ 3000 Series Desktop Processors :
1 x M.2_1 socket 3, with M Key, Type 2242/2260/2280 (PCIE 4.0 x4 and SATA modes) storage devices support
AMD Ryzen™ 4000 G-Series/ 3000 G-Series/ 2000 Series/ 2000 G-Series Desktop Processors :
1 x M.2_1 socket 3, with M Key, Type 2242/2260/2280 (PCIE 3.0 x4 and SATA modes) storage devices support
AMD X570 chipset :
1 x M.2_2 socket 3, with M Key, Type 2242/2260/2280/22110(PCIE 4.0 x4 and SATA modes) storage devices support
6 x SATA 6Gb/s port(s)

 

[Math Geek]

every board is different in how the lanes are divided up. normally you don't run into ports being disabled until you start using a second m.2 slot or pcie slot. but budget boards can disable sata ports when the first m.2 slot is used. you have to look on a case by case basis. i have a b450 aorus pro and it disables 2 sata ports with the first m.2 drive. but it has 6 of them so i don't miss 2 of them at all.

you did read the rest right though, the 2000 series does not support pcie 4.0 so all of this is not applicable with the 2700x. you get pcie 3.0 no matter what board you use. it's just not possible to get top priced performance out of budget parts. if it was possible, no one would buy the high end stuff. you may want to save up a bit more so you can go with the 3000 series cpu's. i'm seeing the 3700x for about $40 more than the 2700x in the US. would be worth the time to save a bit more to help with your objectives.

when scanning specs note than you are more worried about the m.2 slots staying at x4 than you are the pcie slot staying at x16. the gpu won't fill the bandwidth anyway with 3.0 x 16 so dropping to x8 won't bother anything but the highest end gpu's which you are not looking at anyway. but an m.2 slot dropping to x2 will make a noticeable difference.

keep that in mind as you look for options and what compromises have to be made.

 

[Hardquery]

rest right though, the 2000 series does not support pcie 4.0 so all of this is not applicable with the 2700x. you get pcie 3.0 no matter what board you use. ......

@Math Geek thank you buddy for good advice and the opinion affirmation I m seeking for. yes I agree with you that 2700x supports pcie 3.0. but I want to confirm thats in configuration that of m2_2 shares lanes with x570 chipsetand and works in p4x4 and m2_1 shares channel from cpu will work in pcie3x4. So in 2700x will everything work In pcie 3.0 or will the components sharing channel from x570 will work with pcie 4.0 or not.

MD X570 chipset :
1 x M.2_2 socket 3, with M Key, Type 2242/2260/2280/22110(PCIE 4.0 x4 and SATA

In pcie slot pcie_1 with 2700x will be pcie3.0x16 and pcie_2 will be pcie 4.0x4 mode.


AMD X570 chipset
1 x PCIe 4.0 x16 (max at x4 mode)
3 x PCIe 4.0 x1

when scanning specs note than you are more worried about the m.2 slots staying at x4 than you are the pcie slot staying at x16. the gpu won't fill the bandwidth anyway with 3.0 x 16 so dropping to x8 won't bother anything but the highest end gpu's which you are not looking at anyway. but an m.2 slot dropping to x2 will make a noticeable difference

@Math Geek bro yes that what I was thinking that in Asus Rog strix b450-F that GPU if put in Pice 3.0x16 which downgraded to Pice 3.0x8 if m2.2 will be used then what what will be GPU performance reflect in video editing or rendering.

Secondly I want to ask that there is a Asus hyper m.2 x16 adapter card which says it have four m.2 slot work in 128gbps of m.2 drive I think if in place of using m.2_2 I put the card in economical board and put that card in pciex16 slot and take the speed from the slot as we have to already comprise the pciex16 slot....but it requires at least Pice 3.0x16...is there any boards which have b450 or x470 2 Pice 3.0x16 slot in one which I can put GPU and another I can put m.2 adapter card.

 

[Math Geek]

no you don't get any pcie 4.0 lanes with the 2700x. no matter where they are on the board. which means your second idea is not really going to work either.

you are better off buying a bigger single drive than trying multiple smaller ones with the 2700x. by the time you get that adapter and multiple smaller drives, you have probably spent the same amount as a single large m.2 drive.

honestly if it matters that much to you, i'd wait a bit longer and get a 3700x instead. this will avoid a lot of these issues and a lot of headaches