[SOLVED] PCI-E lanes Issue. Ryzen 5 3600 + MSI B450M PRO VDH

[Vishal_7]

Desktop Specs:
CPU: Ryzen 5 3600 all stock
MOBO: MSI B450M PRO VDH
SSD: ADATA SU650 480GB SSD
HDD: Western Digital Blue 1TB 7.2k rpm HDD
GPU: Asus Strix Radeon RX 570 OC
CPU Cooler: DeepCool Gammaxx S40
RAM: Corsair Vengeance LPX DDR4 CL16 3000MHz 8GB*2
PSU: Corsair CX450 PSU
Cabinet: Corsair Carbide SPEC 04 cabinet.

There is only one x16 slot and only 1 M.2 slot in my mobo.
spec page: Here

Currently I have one sata ssd and one 7.2k rpm HDD sata connected. I want to use the M.2 slot .

Few questions which I wanted to ask are:

1. So ryzen 5 3600 has 24 PCI-E 4.0 lanes. my mobo supports max 3.0 speeds. So the configuration can be [as mentioned on wikichip]
Configuration:
1x16+x4 = one GPU using x16 slot and 4 lanes [those 4 lane are for ??]
, 2x8+x4, = 2 GPU using x16 slot but operating at x8 speeds and 4 lanes available ?? (in my case only one x16 slot is available so not possible) [those 4 lane are for ??]
1x8+2x4+x4 = what is this ? means what kind of devices will be connected when this is the operating situation ? (GPU,ethercard , sound card,some device ??)

it is a fact that a mainstream GPU operating at x8 and x16 speeds are of negligible performance difference [unlike 2080ti which saturates x8]. then for x4 speeds the gpu performance goes down. So what are those 4 lanes used for ??
also that all the above configs add to 20lanes. so 4 lanes are for chipset ??? what are those used for ?? are those used for usb etc

2. If I try to use all 4 sata ports of my mobo and also use the M.2 slot , will 2 sata slots not work ? [saw many people saying the same]. will it be the same in my case ?

3. How many lanes do sata ports use ? or m.2 slots use ? if all 4 sata ports and m.2slot is being used, will there be any performance affect ?

4. My mobo M.2 slot speed is PCIe 3.0 x4 . is it ok for nvme drives ? will it slow down or will it operate fine ?

5. there are 2 x PCIe 2.0 x1 slots . what will /can i use them for ? I've heard like ssd can be used in pcie slots with some tray[some caddy like thing] ???

6. is it like the chipset also has its dedicated lanes or it shares from the CPU ? Do other boards have extra chipset for lanes ? Do x570 have separate lanes as well?

Thank you for the replies. Really confused about how the stuff works. tried to understand but didnt got everything cleared.

 

[cdrkf]

Desktop Specs:
CPU: Ryzen 5 3600 all stock
MOBO: MSI B450M PRO VDH
SSD: ADATA SU650 480GB SSD
HDD: Western Digital Blue 1TB 7.2k rpm HDD
GPU: Asus Strix Radeon RX 570 OC
CPU Cooler: DeepCool Gammaxx S40
RAM: Corsair Vengeance LPX DDR4 CL16 3000MHz 8GB*2
PSU: Corsair CX450 PSU
Cabinet: Corsair Carbide SPEC 04 cabinet.

There is only one x16 slot and only 1 M.2 slot in my mobo.
spec page: Here

Currently I have one sata ssd and one 7.2k rpm HDD sata connected. I want to use the M.2 slot .

Few questions which I wanted to ask are:

1. So ryzen 5 3600 has 24 PCI-E 4.0 lanes. my mobo supports max 3.0 speeds. So the configuration can be [as mentioned on wikichip]
Configuration:
1x16+x4 = one GPU using x16 slot and 4 lanes [those 4 lane are for ??]
, 2x8+x4, = 2 GPU using x16 slot but operating at x8 speeds and 4 lanes available ?? (in my case only one x16 slot is available so not possible) [those 4 lane are for ??]
1x8+2x4+x4 = what is this ? means what kind of devices will be connected when this is the operating situation ? (GPU,ethercard , sound card,some device ??)

it is a fact that a mainstream GPU operating at x8 and x16 speeds are of negligible performance difference [unlike 2080ti which saturates x8]. then for x4 speeds the gpu performance goes down. So what are those 4 lanes used for ??
also that all the above configs add to 20lanes. so 4 lanes are for chipset ??? what are those used for ?? are those used for usb etc

2. If I try to use all 4 sata ports of my mobo and also use the M.2 slot , will 2 sata slots not work ? [saw many people saying the same]. will it be the same in my case ?

3. How many lanes do sata ports use ? or m.2 slots use ? if all 4 sata ports and m.2slot is being used, will there be any performance affect ?

4. My mobo M.2 slot speed is PCIe 3.0 x4 . is it ok for nvme drives ? will it slow down or will it operate fine ?

5. there are 2 x PCIe 2.0 x1 slots . what will /can i use them for ? I've heard like ssd can be used in pcie slots with some tray[some caddy like thing] ???

6. is it like the chipset also has its dedicated lanes or it shares from the CPU ? Do other boards have extra chipset for lanes ? Do x570 have separate lanes as well?

Thank you for the replies. Really confused about how the stuff works. tried to understand but didnt got everything cleared.

1: Those configurations are for the PCIe expansion slots and are mainly used for if you are using multiple PCIe devices (e.g. multi gpu for mining). If you have the first slot running at x16, you have 4 lanes remaining for all the other slots. That also leads to point 5- PCIe x1 slots are often used for things that don't need much bandwidth, e.g. network cards (at least entry level models), sound cards and so on. You can as you mention get PCIe based SSD drives (Inte's original Optane drives were PCIe cards for example) these usually require a full size slot running at x4 speed though.

2: The sata ports are connected to the chipset (which has it's own dedicated set of lanes from the CPU). The M2 slot is wired directly to the CPU and has it's own x4 interface which is separate from the allocation of lanes to either the chipset or the graphics card so using the M2 slot shouldn't prevent you using sata ports.

3: There are 4 pcie lanes from the CPU to the chipset- these are shared by all devices attached to the chipset which includes the integrated lan, sound, sata controllers and so on. They don't eat into the other lanes.

4: Yes, PCIe 3 x 4 is the standard for most NVME drives. There are a few PCIe 4.0 drives available now which operate faster- these should still work but will be limited to PCIe 3 x 4 speeds (which tops out around 3000 mb/sec if I remember). A PCIe 3.0 x 4 NVME drive is still really fast though and it's worth keeping in mind, in real usage even the fastest PCIe 4.0 NVME drive doesn't really perform any faster than a high end Sata SSD where the workloads are mixed with random read / write and so on. A good example would be game loading- a Sata 3 SSD (max speed 600mb / sec) and top NVME drive provide the same loading speed as the speed of the memory chips on the drive itself become the limiting factor not the interface. The NVME drives do provide a big speed boost for things like copying large files and so on, where it's a continuous transfer rather than random access.

6: There are separate lanes that connect the chipset to the CPU. All devices linked to the chipset share these lanes. This is the case for X570 as well (although in the case of X570 as the lanes are upgraded to PCIe 4 that chipset has more bandwidth than on older boards).

 

[drea.drechsler]

Desktop Specs:
CPU: Ryzen 5 3600 all stock
MOBO: MSI B450M PRO VDH
SSD: ADATA SU650 480GB SSD
HDD: Western Digital Blue 1TB 7.2k rpm HDD
GPU: Asus Strix Radeon RX 570 OC
CPU Cooler: DeepCool Gammaxx S40
RAM: Corsair Vengeance LPX DDR4 CL16 3000MHz 8GB*2
PSU: Corsair CX450 PSU
Cabinet: Corsair Carbide SPEC 04 cabinet.

There is only one x16 slot and only 1 M.2 slot in my mobo.
spec page: Here

Currently I have one sata ssd and one 7.2k rpm HDD sata connected. I want to use the M.2 slot .

Few questions which I wanted to ask are:

1. So ryzen 5 3600 has 24 PCI-E 4.0 lanes. my mobo supports max 3.0 speeds. So the configuration can be [as mentioned on wikichip]
Configuration:
1x16+x4 = one GPU using x16 slot and 4 lanes [those 4 lane are for ??]
, 2x8+x4, = 2 GPU using x16 slot but operating at x8 speeds and 4 lanes available ?? (in my case only one x16 slot is available so not possible) [those 4 lane are for ??]
1x8+2x4+x4 = what is this ? means what kind of devices will be connected when this is the operating situation ? (GPU,ethercard , sound card,some device ??)

it is a fact that a mainstream GPU operating at x8 and x16 speeds are of negligible performance difference [unlike 2080ti which saturates x8]. then for x4 speeds the gpu performance goes down. So what are those 4 lanes used for ??
also that all the above configs add to 20lanes. so 4 lanes are for chipset ??? what are those used for ?? are those used for usb etc

2. If I try to use all 4 sata ports of my mobo and also use the M.2 slot , will 2 sata slots not work ? [saw many people saying the same]. will it be the same in my case ?

3. How many lanes do sata ports use ? or m.2 slots use ? if all 4 sata ports and m.2slot is being used, will there be any performance affect ?

4. My mobo M.2 slot speed is PCIe 3.0 x4 . is it ok for nvme drives ? will it slow down or will it operate fine ?

5. there are 2 x PCIe 2.0 x1 slots . what will /can i use them for ? I've heard like ssd can be used in pcie slots with some tray[some caddy like thing] ???

6. is it like the chipset also has its dedicated lanes or it shares from the CPU ? Do other boards have extra chipset for lanes ? Do x570 have separate lanes as well?

Thank you for the replies. Really confused about how the stuff works. tried to understand but didnt got everything cleared.

2: you can install 4 SATA drives and as well occupy the M.2 slot.

3. the 4 SATA slots are connected to the SATA controller that's in the chipset. The NVME slot is attached to 4 PCIe lanes that come from a Ryzen CPU itself. It will not impact performance to occupy all 4 SATA as well as the M.2 simultaneously

4. NVME and PCIE is effectively the same thing, so yes your M.2 slot is OK for NVME. It will operate a PCIe x4 gen 3 NVME at it's fullest potential when you have a Ryzen CPU installed.

5. If you've a GPU installed it will probably cover one of the PCIe x1 slots making it inaccessible. You can install an SSD controller/adapter in the other slot but it will operate at gen2, x1 speed which would be inadequate for any sort of NVME. It may be OK for one or two SATA SSD's but that depends on the specific controller.

X570 chipset boards have more lanes than B450 but the lanes available from the CPU are the same whichever board you get. To my knowledge the available CPU lanes are always used 16 to the CPU and 4 to an M.2 NVME socket.

 

[Vishal_7]

@cdrkf Thank you so much for the detailed response. So as i get it. those lanes are for PCIE express slots. Currently I have a gpu that means it uses 16 lanes, correct ?
so 8 lanes left right ?
4 are connected directly to m.2 slot right ?
rest 4 of which are dedicated to chipset to which the USB 3,2, lan port etc are interacting connected right ?

also that There is only one x16 slot and only 1 M.2 slot in my mobo. so there is no point of any performance hit whatsoever for either gpu, m.2 slot drive or sata drives ?

Did i get it correct ?

 

[Vishal_7]

@drea.drechsler Thank you so much for the detailed answer. yup one of the x1 slots is non useful as it has already been blocked by the dual slot gpu. I don't want to go with any adapter or anything. I was just wondering how the stuff works in the mobo. Thank you for the response.

 

[cdrkf]

@cdrkf Thank you so much for the detailed response. So as i get it. those lanes are for PCIE express slots. Currently I have a gpu that means it uses 16 lanes, correct ?
so 8 lanes left right ?
4 are connected directly to m.2 slot right ?
rest 4 of which are dedicated to chipset to which the USB 3,2, lan port etc are interacting connected right ?

also that There is only one x16 slot and only 1 M.2 slot in my mobo. so there is no point of any performance hit whatsoever for either gpu, m.2 slot drive or sata drives ?

Did i get it correct ?

I think the 4 lanes for the M2 are part of the total 24, so 16 for gpu, 4 for remaining PCIe devices, and 4 for M2 = 24. The 4 lanes for the chipset are counted separately.

You are correct there should be no performance hit for using the M2 slot + gpu + sata together.

 

[Vishal_7]

I think the 4 lanes for the M2 are part of the total 24, so 16 for gpu, 4 for remaining PCIe devices, and 4 for M2 = 24. The 4 lanes for the chipset are counted separately.

You are correct there should be no performance hit for using the M2 slot + gpu + sata together.

Thank you for confirming.

 

[drea.drechsler]

I think the 4 lanes for the M2 are part of the total 24, so 16 for gpu, 4 for remaining PCIe devices, and 4 for M2 = 24. The 4 lanes for the chipset are counted separately.
....

I've always seen it as a Ryzen CPU provides 24 lanes, usually allocated as you say to GPU(16), NVME (4) and to chipset(4). But if it actually 'has' 28, maybe the other 4 are allocated internal to the CPU for things like the USB ports that tie directly to the CPU.

You don't often see it implemented this way, but Ryzen truely is a full-on SoC. You don't really need a supporting chipset to build a full-function PC as it provides all that's needed right from the CPU itself. In such an implementation the 4 unused PCIe lanes normally feeding the chipset could be used for, LAN, Audio (assuming it's a CPU) interface and maybe even a couple SATA drives. It would be 'gimped' only in terms of connectivity, not performance.

 

[Vishal_7]

@cdrkf @drea.drechsler thank you once again guys.