[SOLVED] Why would an NVME device be downgraded from 16GT/s to 8GT/s?

Hi,

Why would an NVME device be downgraded from 16GT/s to 8GT/s ?
See the following line:
LnkSta: Speed 8GT/s (downgraded), Width x4
So, my PCIe gen 4 NVME storage is only running at PCIe gen 3 speeds when placed in a FW16 Laptop. Does anyone else see the same, or are others able to get NVME to run at 16GT/s ?
Using FW16 BIOS 3.03.
This is causing the NVME to run at half the speed mentioned in benchmarks.
I.e. 1800MB/s instead of the benchmark 3715MB/s

lspci -vv

02:00.0 Non-Volatile memory controller: Sandisk Corp WD Black SN850X NVMe SSD (rev 01) (prog-if 02 [NVM Express])
        Subsystem: Sandisk Corp WD Black SN850X NVMe SSD
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 0, Cache Line Size: 64 bytes
        Interrupt: pin A routed to IRQ 64
        IOMMU group: 13
        Region 0: Memory at 90a00000 (64-bit, non-prefetchable) [size=16K]
        Capabilities: [80] Power Management version 3
                Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [90] MSI: Enable- Count=1/32 Maskable- 64bit+
                Address: 0000000000000000  Data: 0000
        Capabilities: [b0] MSI-X: Enable+ Count=65 Masked-
                Vector table: BAR=0 offset=00003000
                PBA: BAR=0 offset=00002000
        Capabilities: [c0] Express (v2) Endpoint, MSI 00
                DevCap: MaxPayload 512 bytes, PhantFunc 0, Latency L0s <1us, L1 unlimited
                        ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ SlotPowerLimit 0W
                DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq-
                        RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+ FLReset-
                        MaxPayload 256 bytes, MaxReadReq 512 bytes
                DevSta: CorrErr+ NonFatalErr- FatalErr- UnsupReq+ AuxPwr- TransPend-
                LnkCap: Port #0, Speed 16GT/s, Width x4, ASPM L1, Exit Latency L1 <8us
                        ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+
                LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
                        ExtSynch+ ClockPM+ AutWidDis- BWInt- AutBWInt-
                LnkSta: Speed 8GT/s (downgraded), Width x4
                        TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
                DevCap2: Completion Timeout: Range B, TimeoutDis+ NROPrPrP- LTR+
                         10BitTagComp+ 10BitTagReq- OBFF Not Supported, ExtFmt+ EETLPPrefix-
                         EmergencyPowerReduction Not Supported, EmergencyPowerReductionInit-
                         FRS- TPHComp- ExtTPHComp-
                         AtomicOpsCap: 32bit- 64bit- 128bitCAS-
                DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis- LTR+ 10BitTagReq- OBFF Disabled,
                         AtomicOpsCtl: ReqEn-
                LnkCap2: Supported Link Speeds: 2.5-16GT/s, Crosslink- Retimer+ 2Retimers+ DRS-
                LnkCtl2: Target Link Speed: 16GT/s, EnterCompliance- SpeedDis-
                         Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
                         Compliance Preset/De-emphasis: -6dB de-emphasis, 0dB preshoot
                LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete+ EqualizationPhase1+
                         EqualizationPhase2+ EqualizationPhase3+ LinkEqualizationRequest-
                         Retimer- 2Retimers- CrosslinkRes: unsupported
        Capabilities: [100 v2] Advanced Error Reporting
                UESta:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
                UEMsk:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
                UESvrt: DLP+ SDES- TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
                CESta:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
                CEMsk:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
                AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn-
                        MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap-
                HeaderLog: 00000000 00000000 00000000 00000000
        Capabilities: [1b8 v1] Latency Tolerance Reporting
                Max snoop latency: 1048576ns
                Max no snoop latency: 1048576ns
        Capabilities: [300 v1] Secondary PCI Express
                LnkCtl3: LnkEquIntrruptEn- PerformEqu-
                LaneErrStat: 0
        Capabilities: [900 v1] L1 PM Substates
                L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1- L1_PM_Substates+
                          PortCommonModeRestoreTime=32us PortTPowerOnTime=10us
                L1SubCtl1: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1-
                           T_CommonMode=0us LTR1.2_Threshold=188416ns
                L1SubCtl2: T_PwrOn=150us
        Capabilities: [910 v1] Data Link Feature <?>
        Capabilities: [920 v1] Lane Margining at the Receiver <?>
        Capabilities: [9c0 v1] Physical Layer 16.0 GT/s <?>
        Kernel driver in use: nvme
        Kernel modules: nvme

Were you on battery?
there is a bios setting to reduce pcie speeds while on battery.

1 Like

Ah! That was it.
Plug in power…:

lspci -vv

02:00.0 Non-Volatile memory controller: Sandisk Corp WD Black SN850X NVMe SSD (rev 01) (prog-if 02 [NVM Express])
        Subsystem: Sandisk Corp WD Black SN850X NVMe SSD
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 0, Cache Line Size: 64 bytes
        Interrupt: pin A routed to IRQ 64
        IOMMU group: 13
        Region 0: Memory at 90a00000 (64-bit, non-prefetchable) [size=16K]
        Capabilities: [80] Power Management version 3
                Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [90] MSI: Enable- Count=1/32 Maskable- 64bit+
                Address: 0000000000000000  Data: 0000
        Capabilities: [b0] MSI-X: Enable+ Count=65 Masked-
                Vector table: BAR=0 offset=00003000
                PBA: BAR=0 offset=00002000
        Capabilities: [c0] Express (v2) Endpoint, MSI 00
                DevCap: MaxPayload 512 bytes, PhantFunc 0, Latency L0s <1us, L1 unlimited
                        ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ SlotPowerLimit 0W
                DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq-
                        RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+ FLReset-
                        MaxPayload 256 bytes, MaxReadReq 512 bytes
                DevSta: CorrErr+ NonFatalErr- FatalErr- UnsupReq+ AuxPwr- TransPend-
                LnkCap: Port #0, Speed 16GT/s, Width x4, ASPM L1, Exit Latency L1 <8us
                        ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+
                LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
                        ExtSynch+ ClockPM+ AutWidDis- BWInt- AutBWInt-
                LnkSta: Speed 16GT/s, Width x4
                        TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
                DevCap2: Completion Timeout: Range B, TimeoutDis+ NROPrPrP- LTR+
                         10BitTagComp+ 10BitTagReq- OBFF Not Supported, ExtFmt+ EETLPPrefix-
                         EmergencyPowerReduction Not Supported, EmergencyPowerReductionInit-
                         FRS- TPHComp- ExtTPHComp-
                         AtomicOpsCap: 32bit- 64bit- 128bitCAS-
                DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis- LTR+ 10BitTagReq- OBFF Disabled,
                         AtomicOpsCtl: ReqEn-
                LnkCap2: Supported Link Speeds: 2.5-16GT/s, Crosslink- Retimer+ 2Retimers+ DRS-
                LnkCtl2: Target Link Speed: 16GT/s, EnterCompliance- SpeedDis-
                         Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
                         Compliance Preset/De-emphasis: -6dB de-emphasis, 0dB preshoot
                LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete+ EqualizationPhase1+
                         EqualizationPhase2+ EqualizationPhase3+ LinkEqualizationRequest-
                         Retimer- 2Retimers- CrosslinkRes: unsupported
        Capabilities: [100 v2] Advanced Error Reporting
                UESta:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
                UEMsk:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
                UESvrt: DLP+ SDES- TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
                CESta:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
                CEMsk:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
                AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn-
                        MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap-
                HeaderLog: 00000000 00000000 00000000 00000000
        Capabilities: [1b8 v1] Latency Tolerance Reporting
                Max snoop latency: 1048576ns
                Max no snoop latency: 1048576ns
        Capabilities: [300 v1] Secondary PCI Express
                LnkCtl3: LnkEquIntrruptEn- PerformEqu-
                LaneErrStat: 0
        Capabilities: [900 v1] L1 PM Substates
                L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1- L1_PM_Substates+
                          PortCommonModeRestoreTime=32us PortTPowerOnTime=10us
                L1SubCtl1: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1-
                           T_CommonMode=0us LTR1.2_Threshold=188416ns
                L1SubCtl2: T_PwrOn=150us
        Capabilities: [910 v1] Data Link Feature <?>
        Capabilities: [920 v1] Lane Margining at the Receiver <?>
        Capabilities: [9c0 v1] Physical Layer 16.0 GT/s <?>
        Kernel driver in use: nvme
        Kernel modules: nvme

1 Like