I'm testing the performances of my new SSD card, and it seems I'm stuck with sata2 speed even if my controller is sata3.
Here is the command I'm using.
dd if=tempfile of=/dev/null bs=1M count=1024
1024+0 records in
1024+0 records out
1073741824 bytes (1,1 GB) copied, 0,309558 s, 3,5 GB/s
I got 3,5GB/s even if my device is SATA3:
dmesg | grep SATA
[ 7.035956] ahci 0000:00:1f.2: AHCI 0001.0300 32 slots 6 ports 6 Gbps 0x5 impl SATA mode
[ 7.051861] ata1: SATA max UDMA/133 abar m2048@0xf7a16000 port 0xf7a16100 irq 43
[ 7.051866] ata3: SATA max UDMA/133 abar m2048@0xf7a16000 port 0xf7a16200 irq 43
[ 7.368593] ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
[ 7.368621] ata3: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
hdparm -iI /dev/sda | grep SATA
Transport: Serial, ATA8-AST, SATA 1.0a, SATA II Extensions, SATA Rev 2.5, SATA Rev 2.6, SATA Rev 3.0
Here is my controller:
lspci | grep SATA
00:1f.2 SATA controller: Intel Corporation 7 Series Chipset Family 6-port SATA Controller [AHCI mode] (rev 04)
This is the hdparam test:
hdparm -I /dev/sda | grep -i speed
* Gen1 signaling speed (1.5Gb/s)
* Gen2 signaling speed (3.0Gb/s)
* Gen3 signaling speed (6.0Gb/s)
Partition alignment should be ok (I'm not 100% sure).
(parted) p
Model: ATA Samsung SSD 840 (scsi)
Disk /dev/sda: 250GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Number Start End Size Type File system Flags
1 1049kB 92,9GB 92,9GB primary ext4
4 92,9GB 94,0GB 1128MB primary ext4 boot
2 94,0GB 241GB 147GB primary ext4
3 241GB 250GB 9222MB primary linux-swap(v1)
(parted) align-check opt 1
1 aligned
(parted) align-check opt 2
2 aligned
(parted) align-check opt 3
3 aligned
(parted) align-check opt 4
4 aligned
Bios is configured correctly with AHCI
My laptop is an Asus A55VD, SSD is Samsung EVO 840.
Why I'm having 3GB/s instead of 6GB/s?
Is perhaps my disk alignment not correct?
Thanks
dd
implies that you had previously accessed tempfile, so that most of its data were cached. The test usingdd
would have some validity only if the SSD had not been accessed since the system was booted, but it would then show less than the drive maximum because of OS and application overheads.