Hi Chino, thanks for your reply.
To avoid trailing multiple Acronis Backup installs (at this stage), I reset my moderate overclock (to 4GHz via the AI Suite 5-way tuner) back to defaults in the BIOS, then updated to BIOS 0901 (PCIE_X4_1 potential future issue resolved). Then, using the motherboard install CD I reinstalled both sets of USB3 drivers then installed the USB3 Boost from the AI Suite3 options.
On a positive note, this has now allowed me to connect the Seagate HDD at will. Additionally, I have confirmed that xHCI is enabled and that I'm connecting to a USB3 port (tried both controllers ASMedia back plate ports (blue) and the front case, via Intel motherboard header), Seagate BUP Fast HDD USB3 connection also confirmed by AIDA64. Additionally, I now get access to the Asus USB3 Boost function.
Using the Sisoft File System Bandwidth Benchmark I see the following:
Drive Score : 149.59MB/s
Detailed Results
Buffered Read Bandwidth : 241.89MB/s
Sequential Read Bandwidth : 180.2MB/s
Random Read Bandwidth : 66.16MB/s
Buffered Write Bandwidth : 324.18MB/s
Sequential Write Bandwidth : 245.6MB/s
Random Write Bandwidth : 93.09MB/s
Random Access Time : 9.57ms
This does look more promising, so I tried copying a couple of large files (3GB and 8GB) from the internal Samsung Evo SSD to the Seagate, then backwards.
WRITE from SSD Evo to Seagate pretty much stabilises at 65MB/s (peak around 70)
READ from Seagate to Evo again seems to stabilise at 65MB/s (peak around 78)
So something seems not right here. The Seagate is an expensive portable drive and all online reviews detail significantly higher read/write rates for large (GB) single files. Unfortunately, the USB3 Boost function, when enabled, makes very little difference (Turbo option only…UASP not detected – I’ll need to look into that as I’m sure it’s meant to be a feature).
Anyway, is there anything else I might be missing here?