Yes the SATA ports 1&2 are ASmedia which gave the worst results.. here's the ATTO benchmark using SATA port 3: View: https://imgur.com/a/yL5FHQCthe advertised speeds usually state up to so you may not get that result every time.
The SATA ports may use different drivers either AMD or ASMedia etc...
Also check the SATA ports are configured for AHCI not IDE in bios.
also most SSDs refer to ATTO benchmarks, CDM may give you different results as well.
Indeed the chipset ports are better but the speed is still bad.The ASMEDIA ports will absolutely give you worse performance.