My motherboard provides 4x USB 3.2 Gen1 ports for rear I/O and another 2x USB 3.2 Gen1 ports for front I/O (through the header), but my chipset only supports 2x USB 3.2 Gen1 ports. Where is the support for the other ports coming from?
| Motherboard | Wikipedia |
|---|---|
The motherboard is an ASRock B450M Steel Legend
It seems like only 5 of 6 chipset PCIe lanes are exposed on the board, so it’s totally possible that they used the extra x1 for a USB card.
(The Gen 3 slots come off the CPU, so aren’t counted)
Ah, I think I’m starting to understand this a little better. Is that 4 lanes for SATA and 1 for the PCIe x1 slot?
Where do you reckon the PCIe 2.0 x16 slot’s lanes come from?
Nah SATA is built into the chipset. That second x16 is actually only electrically x4 in an x16 form factor, and there’s that x1 slot, adding up to 5 lanes in total. The first x16 and first nvme slot (x4) are connected to the CPU directly (which IIRC most have 20 lanes on AM4, but not always).
Oh, that makes sense, thanks
My CPU (1600 AF) only has 16 lanes, but I have a graphics card and an NVMe SSD and both seem to be getting all the lanes. I wonder what’s going on here
07:00.0 VGA compatible controller: NVIDIA Corporation TU116 [GeForce GTX 1650 SUPER] (rev a1) (prog-if 00 [VGA controller]) Subsystem: Micro-Star International Co., Ltd. [MSI] TU116 [GeForce GTX 1650 SUPER] [...] LnkCap: Port #0, Speed 8GT/s, Width x16, ASPM L0s L1, Exit Latency L0s <1us, L1 <4us ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+ LnkCtl: ASPM Disabled; RCB 64 bytes, Disabled- CommClk+ ExtSynch- ClockPM+ AutWidDis- BWInt- AutBWInt- LnkSta: Speed 8GT/s (ok), Width x16 (ok) TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
01:00.0 Non-Volatile memory controller: Silicon Motion, Inc. SM2262/SM2262EN SSD Controller (rev 03) (prog-if 02 [NVM Express]) Subsystem: Silicon Motion, Inc. SM2262/SM2262EN SSD Controller [...] LnkCap: Port #0, Speed 8GT/s, Width x4, ASPM L1, Exit Latency L1 <8us ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+ LnkCtl: ASPM Disabled; RCB 64 bytes, Disabled- CommClk+ ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 8GT/s (ok), Width x4 (ok)
Edit:
$ sudo dmidecode --type 9 | grep -E 'Usage|Type|Designation'
Designation: PCIE1
Type: x1 PCI Express
Current Usage: In Use
Designation: PCIE2
Type: x16 PCI Express
Current Usage: In Use
Designation: PCIE3
Type: x1 PCI Express
Current Usage: In Use
Designation: PCIE4_M2_1
Type: x4 PCI Express
Current Usage: In Use
According to https://www.asrock.com/mb/amd/b450m steel legend/ it supports 6 Gen1 and 2 Gen2.