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pawel@paulbook:~$ dmesg | grep -i sata | grep 'link up'
[    2.355461] ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
[    2.691842] ata3: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[29631.906614] ata3: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[29631.914605] ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
[41633.796009] ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
[41633.803999] ata3: SATA link up 1.5 Gbps (SStatus 113 SControl 300)

pawel@paulbook:~$ dmesg | grep -i --color ahci
[    1.994964] ahci 0000:00:1f.2: version 3.0
[    1.995148] ahci 0000:00:1f.2: irq 48 for MSI/MSI-X
[    1.995180] ahci 0000:00:1f.2: SSS flag set, parallel bus scan disabled
[    2.011185] ahci 0000:00:1f.2: AHCI 0001.0300 32 slots 6 ports 6 Gbps 0x35 impl SATA mode
[    2.011191] ahci 0000:00:1f.2: flags: 64bit ncq sntf stag pm led clo pio slum part ems sxs apst 
[    2.035576] scsi0 : ahci
[    2.035697] scsi1 : ahci
[    2.035794] scsi2 : ahci
[    2.035873] scsi3 : ahci
[    2.035939] scsi4 : ahci
[    2.036000] scsi5 : ahci

pawel@paulbook:~$ dmesg | grep -i  ahci | grep -i --color Gbps
[    2.011185] ahci 0000:00:1f.2: AHCI 0001.0300 32 slots 6 ports 6 Gbps 0x35 impl SATA mode

To me it seems that my mainboard has a SATA 6 Gb/s. However, when I benchmark my SSD I get less than 400 MB/s reads even though the vendor claims "550 MB/s sequential reads on both compressible and incompressible data" is available:

pawel@paulbook:~$ sudo hdparm -t /dev/sda

/dev/sda:
 Timing buffered disk reads: 1098 MB in  3.00 seconds = 365.76 MB/sec

Does it mean my mainboard has SATA 3 Gb/s? According to lspci I have Intel Corporation 6 Series/C200 Series Chipset Family but I couldn't find any information in the Internet which SATA is supported.

share|improve this question
    
Have you checked in your BIOS config which transfer mode is enabled for the SATA port on your board? The BIOS setting might limit the speed. –  dobey Jul 15 at 21:12
    
SATA GEN3 is enabled. –  pmichna Jul 15 at 21:13
    
6 Gb/s in reality is 750 MB/s, but this is the maximum interface speed. In my experience, devices that manage the maximum interface speed are non-existent ATM. –  Elder Geek Jul 15 at 21:21
    
Do you get better results if you disconnect the old SATA I device? –  Elder Geek Jul 15 at 21:22
    
The other SATA device is a cd--rom drive, so I'm not going to disconnect it. –  pmichna Jul 15 at 21:26

3 Answers 3

up vote 8 down vote accepted

Well I was going to point you to How to know if hard drive supports Sata3 (6Gb/s) but your question is not what Sata version is supported but if the 400 you are seeing are in fact Sata3.

TIPS WHEN SELECTING A GREAT SSD DRIVE

I actually made a benchmark test with 3 hard drives on the same motherboard found here in Spanish and the things I learned from it were:

  • Not all SSD companies tell you the truth. I don't mean the "in theory it should achieve speeds of..." truth. I mean "I tested this and all I got was this lousy T-shirt". With this I mean that, one thing is what they tell you the SSD can achieve, another is what it actually achieves.

  • Not all SSD models from the same company achieve the same speeds. Or worse, maintain the same speeds for months.

  • Your favorite SSD company might actually be worse than that other new weirdly named company.

  • The motherboard can actually have a huge impact on the SSD's performance.

BENCHMARK (Samsung vs Intel vs Kingston)

Here is the information I gathered while I tested the following models (Noticed I changed the notation to BYTES, not BITS since we want the real world truth):

  • Intel 520 Series 120GB SSD which mentions in theory a READ speed of 550 MB/s and a WRITE speed of 500 MB/s.

  • Kingston SSDNow V300 120GB which mentions in theory a READ speed of 525 MB/s and a WRITE speed of 500 MB/s.

  • Samsung PRO 256GB which mentions in theory a READ speed of 540MB/s and a WRITE speed of 520 MB/s.

BENCHMARK (Results)

I got the following results from 10 tests with the Disks benchmark tool and 3 more with hdparm:

  • For the Intel, it showed an average of 465 MB/s (READ) & 329 MB/s (WRITE) with the Disks Benchmark. With hdparm I got an average of 398 MB/s (READ).

  • For Kingston which was the one I assumed would be the best of all 3 got an average of 404 MB/s (READ) & 298 MB/s (WRITE) with the Disks Benchmark. With hdparm I got 376 MB/s (READ).

  • For Samsung, the Disk Benchmark had a problem doing the Write test, so I could only do the READ test which gave me a 555MB/s. hdparm gave me 519MB/s (READ). Now, since I don't like to leave things half-baked, I did a normal test (10 times) of copying a file from one place to another on the same SSD. I first tried 1GB but it was too fast to test and find an average. I then tested 2GB, then 5GB and at last got to 10GB (Or 10.2GB to be exact) to test this. The average WRITE speed landed at 753MB/s.

So My first thought of seeing the Kingston as the fastest was wrong. Even my second thought of the Intel being the fastest was wrong. It was Samsung. Now I did the test right now again and got a speed of 716MB/s (WRITE). The drop might be X variable on the system but the speed nevertheless is very high.

BENCHMARK (Changing Motherboards)

Here are the impacts if I change motherboard (The previous test was done on an Asus Z87 PRO updated with the latest firmware). If I jump to an Intel DZ68DB which also advertises Sata3 (6.0Gb/s), all SSD drop between 40% to 60% of their speed with the Asus). This is how important the motherboard is. If you have a low cost motherboard with a high cost SSD, well, you just wasted your money on the SSD because of the limiting factor the motherboard will have on the SSD. To give you an idea, the Samsung was doing a 265MB/s READ speed and a 212MB/s WRITE on the DZ68DB. That's a huge drop.

Now here is an update for the ASRock H61M/U3S3 & the Gigabyte GA-H77M-D3H.

With the ASRock using the Disk utility 10 times, the Intel SSD got 140MB/s (READ) & 110MB/s (WRITE). the Samsung SSD got 180MB/s (READ) & 123MB/s (WRITE). I don't have the Kingston right now but you can guess from the other two how it would go with it.

With the Gigabyte using the Disk utility 10 times, the Intel SSD got 241MB/s (READ) & 209MB/s (WRITE). the Samsung SSD got 312MB/s (READ) & 295MB/s (WRITE). Again I don't have the Kingston right now but you can guess from the other two how it would go with it.

CONCLUSION

On all cases, hdparm, dmidecode, dmesg and any other HDD/SSD reading tool showed that I was "capable" of using Sata3, but the actual READ/WRITE speeds where not met to the speed one assumes to get from using Sata3 because it varies greatly between motherboards, SSD models and any other variable in between.

With all of this said and done, to answer your question: Is 400MB/s a Sata3 speed?

Yes, yes it is. Sata2 would really limit you from around 180Mb/s to 250MB/s in a real world scenario. Sata3 would push the boundaries well above the 300MB/s. But this is also affected by the motherboard, SSD model & SSD manufacturer.

On Hard Drive Benchmark which I always check to see which SSD to buy or recommend I found that your Crucial MX100 has 3 types of sizes, of which, only 2 appear in that list, the 512 & 256 versions. Each one with their scores. So here are the scores of the benchmarked SSDs I tested with the 3 types:

  • Intel 520 Series 120GB - 3699
  • Kingston SSDNow V300 120GB - 2514
  • Samsung PRO 256GB - 3536
  • Crucial MX100 256GB - 2916
  • Crucial MX100 256GB - 3729 (Model 2)
  • Crucial MX100 512GB - 3480

From the scores one would think the best is the Model 2 of Crucial, followed by Intel, but one would be wrong. Factors like motherboard, firmware version (For both, mobo and SSD), operating system and even BIOS/UEFI settings can change everything.

For my current case, enabling TRIM on the Samsung gave me a boost of about 150MB, which lands me in the 500+ Speeds. I actually did not know TRIM could change the speed until I enabled it. Another factor was updating the Asus firmware.

So yes, you are using Sata3, especially with a 365MB/s speed but something (Maybe motherboard, firmware, the actual SSD, the SSD cable, the geographical location, the altitude, Santa claus, some weird freaky alien electrical monster living inside your computer case, etc....) can have an effect on the actual performance. BTW, some motherboards when using old hardware connected to it, can somehow limit the performance of the rest. For example, having an old PATA CD-ROM or DVD-ROM connected can have a negative performance on the drive. Same goes for a 3.5 Floppy drive (I mean come on O.o).

Updating Ubuntu to a more recent version can have most of the time a positive impact on performance, especially if you read the performance improvements on the 3.14, 3.15 and 3.16 kernels.

share|improve this answer
    
It's SSD, not SDD. –  saiarcot895 Jul 16 at 20:44
1  
@saiarcot895 What are you talking about ;) I feel silly confusing in all instances the word... on a topic ABOUT it. –  Luis Alvarado Jul 16 at 21:38
For Kingston which was the one I assumed would be the best of all 3 got an average of 404 MB/s (READ) & 298 MB/s (WRITE) with the Disks Benchmark. With hdparm I got 376 MB/s (READ).

There is really no sure way to know what you are going to get with a V300 without detailed testing to figure which hardware Kingston provided to you. They pulled a bait and switch with the NAND used in the build of materials. Google the AnandTech article:

'An Update to Kingston SSDNow V300: A Switch to Slower Micron NAND'

for details.

share|improve this answer

Yes you do. When it says 6gbps it is just saying that that is what the maximum speed of the interface is. No drive has reached A gigabyte per second yet that I have heard of so everything is operating just fine and there is no need to worry. All that your system is saying is that the maximum interface speed is 6gbps and your volume is operating at 365.76mbps. When the manufacture says that the speed it 550mbps they are showing the results they got on THEIR system. The speed also depends on your mobo, bus speed, and interface.

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2  
Gb is Gigabit, not Gigabyte –  Elder Geek Jul 15 at 22:03

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