When I was building the Fujitsu TX140 S2, I wanted to purchase a SATA controller to expand the capacity from 6 SATA devices to 12. The ASMedia ASM1166 seemed most interesting as it is a modern design offering six SATA3 6Gbps ports without use of a port multiplier.
Despite what the silk screen on the PCB states, it is not “PCIe 3.0 x4” except in PCIe slot dimensions (since there is no standard for a physical PCIe x2 connector). The ASM1166 has a PCIe 3.0 x2 interface:
So the ASM1166 cannot provide full bandwidth to six SATA3 devices, but it is not as bandwidth limited as other SATA controllers which have only a PCIe x1 host connection. Be aware that the bandwidth will be halved if you install it in a PCIe 2.0 slot, due to the less efficient encoding of PCIe 2.0 (8b/10b) versus PCIe 3.0 (128b/130b).
The board designer did properly route the PCIe x2 connection to the host, as confirmed by
02:00.0 SATA controller: ASMedia Technology Inc. Device 1166 (rev 02) (prog-if 01 [AHCI 1.0]) Subsystem: ZyDAS Technology Corp. Device 2116 Physical Slot: 3 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 26 Region 0: Memory at f7a82000 (32-bit, non-prefetchable) [size=8K] Region 5: Memory at f7a80000 (32-bit, non-prefetchable) [size=8K] Expansion ROM at f7a00000 [disabled] [size=512K] Capabilities:  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:  MSI: Enable+ Count=1/1 Maskable- 64bit+ Address: 00000000fee00298 Data: 0000 Capabilities:  Express (v2) Endpoint, MSI 00 DevCap: MaxPayload 512 bytes, PhantFunc 0, Latency L0s <64ns, L1 <1us ExtTag+ AttnBtn- AttnInd- PwrInd- RBE+ FLReset- SlotPowerLimit 75.000W DevCtl: CorrErr+ NonFatalErr+ FatalErr+ UnsupReq- RlxdOrd- ExtTag+ PhantFunc- AuxPwr- NoSnoop+ MaxPayload 128 bytes, MaxReadReq 512 bytes DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr- TransPend- LnkCap: Port #0, Speed 8GT/s, Width x2, ASPM L0s L1, Exit Latency L0s <4us, L1 <64us ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+ LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk+ ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 8GT/s (ok), Width x2 (ok) TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- DevCap2: Completion Timeout: Not Supported, 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-, OBFF Disabled AtomicOpsCtl: ReqEn- LnkCtl2: Target Link Speed: 8GT/s, EnterCompliance- SpeedDis- Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS- Compliance De-emphasis: -6dB LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete+, EqualizationPhase1+ EqualizationPhase2+, EqualizationPhase3+, LinkEqualizationRequest- Capabilities: [100 v1] 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: [130 v1] Secondary PCI Express LnkCtl3: LnkEquIntrruptEn-, PerformEqu- LaneErrStat: 0 Kernel driver in use: ahci
Power consumption is very good, the card only draws 2.8W idle.
PCIe SATA controllers based on the ASM1166 are comparatively priced to other 5-6 port SATA controllers, but offer more bandwidth than cards using the JMicron JMB585 or Marvell 88SE9125. ASM1166 controllers can be found for around 20€ on AliExpress. There are seemingly some sellers shipping cards with PCIe x1 connectors, so I would advise you to check the reviews of other customers to see which variant the seller sends.
I was unable to find detailed information about the card such as power consumption and
lspci output online, which I find very useful when making purchasing decisions, so I thought I should write a short summary. This is not a review or endorsement of any online marketplace or brand.