Ubuntu – How to check/enable the full speed of SATA drive/port

Recently I've got mSata SSD and install it in my laptop.

According to the specification of this SSD, the read rate is approximately 450 MB/s.
I tested the read rate (in menu Application > Accessories > Disks > Benchmark Disk) and got the smaller value 280 MB/s.

Digging around I got the following result:

$ sudo smartctl -a /dev/sdb | grep SATA
SATA Version is:  SATA 3.2, 6.0 Gb/s (current: 3.0 Gb/s)

How can I enable the full speed 6.0 Gb/s?

OR

How can I check the maximal speed of SSD/port/something?

How can I identify the device (SSD/port/something) reducing the resulting speed?

Thank you in advance!

Additional information:

$ sudo hdparm -I /dev/sdb | grep SATA
Transport:          Serial, ATA8-AST, SATA 1.0a, SATA II Extensions, SATA Rev 2.5, SATA Rev 2.6, SATA Rev 3.0

$ sudo hdparm -I /dev/sdb | grep speed
   *    Gen1 signaling speed (1.5Gb/s)
   *    Gen2 signaling speed (3.0Gb/s)
   *    Gen3 signaling speed (6.0Gb/s)

$ lspci | grep SATA
00:1f.2 SATA controller: Intel Corporation 7 Series Chipset Family 6-port SATA Controller [AHCI mode] (rev 04)

$ dmesg | grep ata
[    0.000000] BIOS-e820: [mem 0x00000000baf9f000-0x00000000baffefff] ACPI data
[    0.000000] Memory: 7968868K/8242108K available (12300K kernel code, 2481K rwdata, 4012K rodata, 2368K init, 2372K bss, 273240K reserved, 0K cma-reserved)
[    0.122082] libata version 3.00 loaded.
[    1.186115] Write protecting the kernel read-only data: 18432k
[    1.448965] wmi_bus wmi_bus-PNP0C14:00: WQBC data block query control method not found
[    1.489423] ata1: SATA max UDMA/133 abar m2048@0xd0618000 port 0xd0618100 irq 26
[    1.489478] ata2: DUMMY
[    1.489508] ata3: SATA max UDMA/133 abar m2048@0xd0618000 port 0xd0618200 irq 26
[    1.489555] ata4: SATA max UDMA/133 abar m2048@0xd0618000 port 0xd0618280 irq 26
[    1.490239] ata5: DUMMY
[    1.490268] ata6: DUMMY
[    1.802539] ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[    1.802567] ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[    1.802591] ata4: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[    1.802676] ata3.00: ATA-11: MT-64, 1.74.00, max UDMA/133
[    1.802685] ata3.00: 125045424 sectors, multi 16: LBA48 NCQ (depth 31/32), AA
[    1.802787] ata3.00: configured for UDMA/133
[    1.811416] ata4.00: ATAPI: TSSTcorp DVD+/-RW SN-208BB, D300, max UDMA/100
[    1.813156] ata1.00: ATA-8: ST9750420AS, 0005DEM1, max UDMA/133
[    1.813160] ata1.00: 1465149168 sectors, multi 16: LBA48 NCQ (depth 31/32)
[    1.815466] ata4.00: configured for UDMA/100
[    1.850643] ata1.00: configured for UDMA/133
[    8.712553] EXT4-fs (sdb1): mounted filesystem with ordered data mode. Opts: (null)
[    9.973968] EXT4-fs (sdb2): mounted filesystem with ordered data mode. Opts: (null)
[   11.987641] EXT4-fs (sda3): mounted filesystem with ordered data mode. Opts: (null)
[   12.056330] EXT4-fs (sda6): mounted filesystem with ordered data mode. Opts: (null)

UPD:

$ dmesg | grep AHCI
[    1.471403] ahci 0000:00:1f.2: AHCI 0001.0300 32 slots 6 ports 6 Gbps 0xd impl SATA mode