Review on 🔘 Syba SD-PEX50055: High-Speed 2 Port USB 3.0 and 2 Port SATA III PCIe 2.0 x4 Controller Card – Green Grey by Matt Watson

The card is physically x4, but only uses x2 PCI-E 2.0 lanes. This isn't necessarily a bad thing in itself, since PCI-E 2.0 allows 5 Gb/s per lane (500 MB/s). It's probably x1 for the SATA3 controller which should be 6Gbps but then you only get 5Gbps and x1 for the USB3 controller which is also 5Gbps so that's fine. However, the SATA performance of this card seems to be limited to around 400 MB/s. I won't upload photos of my own tests, but if you look at the hard drive performance tests that others have uploaded, none of them exceeded 400MB/s. So if you are looking to upgrade your system from SATA2 to SATA3, you will only get about a 33% increase in performance compared to the 100% increase in performance you should be getting. However, I didn't bother to check the speed of the USB3 ports. When my mouse was connected to it, I noticed that the mouse pointer would sometimes get stuck for 1-2 seconds during hard drive activity. I found it very annoying and it was a deal breaker for me.