Compuer details:
Z600
24GB RAM
4TB internal drive space
VANTEC UGT-PCE430-4C USB 3.0 Card (Renesas host controller)
External Harddrive Western Digital WDWBBGB0040HKB-NA (4TB)
External Harddrive Segare 1DXAP3-500 (3TB)
Both drives work on 2.0 port but on 3.0 port drive displays root directory, but will not read or write any files, and all computer operations slow to a crawl .
FWIW, Siig USB 3.0 multi card reader SIIGA9V1450X works perfectly
For the HP god of the Internet support forum, if this is not in the right place. please let me know.