We have noticed that some PMC expander products have improperly register settings which may cause communication conflict and result slow performance.
The new controller firmware patches some registers in PMC expander to avoid this problem. In other words, it is not a common issue for all PMC expander products but only for these expanders which change some registers from PMC default.
Tags: ARC-1680, expander, firmware, HDD, SAS, SATA