Anyone found any improvements to their USB 3.0 performance with the New BootROM 138.0.0.0.0?
No, the firmware doesn’t change this. The spec. is the spec., regardless.
Faster transfers over USB 3.1 on a PCIe 2.0 buss should be theoretically possible I believe, if additional lanes are multiplexed with a switch, and put into a wide lane slot, but no such USB 3.1 device exists AFAIK.
No, it doesn’t exist in the real world at the moment, and probably won’t ever. PCIe 2.0 is a dead technology and it wouldn’t make sense, nor would anyone likely buy such an expensive, very limited use device.
What are you doing/using that saturates the bandwidth of a USB 3.0 connection?
640 MB/s - is more than a single SSD on the cMP SATA buss. It’s about the same as 2x 2.5” SSD’s (fast ones) in RAID0 on a cMP SATA BUSS.
The Startech 5-Port USB 3.1 (10Gbps) Combo Card uses the following:
1) Asmedia ASM1142 USB 3.1 gen 2 host controller
2) VIA Lab's VL812 4-port USB 3.0 hub controller
One port of the Asmedia supports 10 Gbps (limited by the PCIe 2.0 x2 of the ASM1142 to 670 MB/s). The other port powers the 4-port hub which supports 5 Gbps per port (400 MB/s?)
A PCIe switch chip can't improve the performance of the Startech beyond the PCIe 2.0x2 link speed/width supported by the ASM1142. However, a switch will give improvements to a card when the card is used in a PCIe 1.0x4 slot (which in some cases may run at only PCIe 1.0x1 if it doesn't support x2 like in my 2008 Mac Pro) or a PCIe 2.0x4 slot that does not support x2 (some PC's with slots connected directly to SandyBridge CPUs for example). The Caldigit FASTA-6GU3 Plus is one such card with a PCIe switch that uses a ASM1142.
To go beyond PCIe 2.0x2 (or PCIe 3.0x1 or PCIe 1.0x4), you need a different USB controller such as the ASM2142 (but a switch is needed to convert its PCIe 3.0x2 to the PCIe 2.0x4 of your MacPro).
Another possibility is the USB controller that is part of a Thunderbolt 3 chip which is used on some newer Macs. Thunderbolt 2 Macs can get the benefit of the USB 3.1 gen 2 of Thunderbolt 3 using an Apple Thunderbolt 3 to Thunderbolt 2 adapter with a Thunderbolt 3 peripheral that has two Thunderbolt 3 ports.
I'm able to use a GC-TITAN RIDGE Thunderbolt add-in card in my MacPro3,1 (Mac Pro 2008) to provide faster USB 3.1 gen 2 speeds (It's a PCIe 3.0x4 card that boots into PCIe 1.0 speed on my 2008 MacPro but can be set to PCIe 2.0 speed using some pciutils commands). It seems to have a read cap of 400 MB/s when used in a PCIe 1.0 slot which is strange because write is not capped (672 MB/s write) and I can get 678 MB/s read in a PCIe 2.0 slot set to PCIe 1.0 speed. The read speed goes up to 872 MB/s when the speed is set to PCIe 2.0.
Mac Pros with the New BootROM 138.0.0.0.0 might not have the problem where the PCIe 3.0 Thunderbolt card (and other PCIe 3.0 cards like the Amfeltec gen 3 carrier) boots into PCIe 1.0 speed.
Thunderbolt functionality doesn't work unless you boot into Windows first. I don't think hot swap works. An NVMe drive should be able to do about 1500 MB/s but I haven't tested that yet.
You would need to use a RAID0 array. Many expensive ways to do that. Google it and choose your poison. Also keep in mind that software RAID0 appears to be dying in the Apple ecosystem. There newest file system doesn’t support it at all.
Read backwards through this thread, or use the search. It’s posted here what the max USB speeds are after subtracting the overhead. I don’t recall offhand.
I'm using a OWC Mercury Elite Pro Dual mini with two SSDs in hardware RAID 0.