SSD not being recognized as AHCI, slow speeds (pics)

My Samsung 840 Pro 256GB SSD is not being recognized as being SSD in the Samsung Magician software.

My bench mark speeds are also very slow.

I am a using Gigabyte P55A-UD3R motherboard.
SSD is connected via the GSATA3_6 port (6GB cable).

I have set every option for Sata in my bios to AHCI before I installed windows OS on my new SSD drive.

Samsung Magician Benchmark Results:

Device Manager:


In my bios it also says:

Can anyone see anything wrong here?
10 answers Last reply Best Answer
More about ssd recognized ahci slow speeds pics
  1. The speeds are definitely faster than IDE speeds. Checking manual...

    I think the IDE Channel is just a label.
  2. Ok I just tried plugging in the SSD Sata cable into the SATA2 port and ran a benchmark.

    It now says AHCI is enabled in the samsung software but gives a warning about not optimizing 6GB/s speeds.

    The IDE Channel list in the BIOS no longer shows my SSD drive either.

    The read speed is now slower, but the write speed is slightly faster.

    Any idea why the GSATA ports aren't working for AHCI but the Sata2 ports are?
    (all drivers installed)
  3. According to your MB manual, the SATA III ports share bandwidth with the PCIe BUS. Your GSATA settings in the BIOS correspond to the Marvell SATA III controller. So the 'Enabled' and subsequent 'AHCI' are correct.

    Update the BIOS to the latest rev. It may just be a hardware compatibility issue. Let us know if that helps.
  4. Hi,

    Thanks for replying but I am not sure you understand.

    My motherboard has Sata 3 ports (two of them, GSATA3_6 and GSATA3_7).

    "Provides newest Marvell SE9128 high speed SATA3 storage interface with superfast 6Gbps link speed"

    I tried these ports with my SSD with AHCI enabled in the bios for them, but for some reason it is not working.

    I then tried the SATA2 ports instead, which AHCI are working on, but slower speeds.

    I would like to get them working on the GSATA3 ports but have no idea why they won't work on them.
  5. Your benchmark results are normal.

    The Marvell SE9128 SATA 3 (6Gb/s) controller on your motherboard has a data bandwidth of PCIe x1 at 5GB/s (500MB/s).

    You will not get advertised Read/Write speeds from any current generation SATA 6Gb/s SSD you connect to those ports.

    Update your drivers for the Marvell controller and see if that will allow Samsung Magician to recognize that your SSD is in AHCI mode.

    Scroll down to the section that reads " Marvell 88SE91xx & 88SE92xx Sata 6G Controllers Drivers & Firmwares".
    Download & run the file named " Drivers Version WHQL" dated 02/10/2013.
  6. Thanks Dereck.

    I managed to get the GSATA ports to become AHCI enabled by plugging the SSD drive into the SATA2 ports, then installing the GSATA drivers again. Maybe they did not install correctly because the port was already occupied but it's working fine now.

    The benchmarks are still slow, I will try those drivers your recommended and report back.

    Basically my only option is to get a new motherboard with better SATA 6Gb/s ports?
  7. rubbed said:
    Basically my only option is to get a new motherboard with better SATA 6Gb/s ports?

    Correct. Current generation SSDs need to be connected to native 6Gb/s ports for maximum performance.

    If you have an Intel CPU then you need a motherboard with Intel 6Gb/s ports.
    If you have an AMD CPU then you need a motherboard with AMD 6Gb/s ports.
  8. Thanks for the info.

    Do you think I should just use the marvel sata ports or downgrade to the Sata2 ports?

    Getting a new mobo is out of the question for now unfortunately.
  9. Best answer
    I would use one of the SATA2 ports.
    Install Intel's latest AHCI drivers (if you haven't done so already).
  10. I have a VERY similar problem to 'rubbed'.
    I too have a Samsung 256 GB 840 Pro. At first when I tried activating ACHI it would not boot but would boot fine when set to 'IDE". Someone said they thought IDE was only a name or tag. In my system BIOS you set the drives to either IDE or ACHI. I was eventually able to activate the ACHI by going into the registry and editing a couple of keys and then it would boot to ACHI. I did benchmarks with both Samsung Magician and CrystalDisk Mark and I did see an improvement in the benchmarks for before ACHI and after.

    However, I have a laptop that I put a Samsung 840 EVO in only 3 weeks before. Both my laptop and my main tower PC are only SATA 2 and both have ACHI activated but the laptop SSD is "FASTER" than my tower PC?

    The laptop (LT) is an ASUS with Intel dual core 2.5 MHz with 4 GB of RAM........... The tower (T) mobo is also an ASUS with a Intel i5 2.85 MHz and 16 GB of RAM
    (LT) 840 EVO SSD speeds are SEQ 532 & 357 and RAND 53729 & 37195... (T) 840 Pro SSD speeds are SEQ 274 & 240 and RAND 49752 & 38015
    Or laptop Seq. 532 vs. tower 274; and LT 357 vs. T 240 = Laptop average 70% faster
    An (T) Random 53729 vs. 49752 & 37195 vs. 38015 = 6% faster

    So there is a huge difference in the sequential read/write where the laptop is 70% fast but in the random read/write only 6% faster! BUT THAT IS an 840 EVO in a LAPTOP average 40% faster than a 840 PRO in a tower PC!
    SOMETHING is obviously wrong??

    ANY HELP will be greatly appreciated.

    TIPS for others (I have learned): First when setting up an SSD disconnect all other drives UNTIL you have the SSD setup and booting with it set to ACHI. Do NOTHING else until you do that.
    Also make sure it is recognized as DISK#0 and ACHI, before you install your OS system. I had an older HDD 1 TB with a lot of data on it, partitioned into 4 drives. When I first booted up it had the partitions ID'd as C: D: E: and F:, which I had to change so I could have the SSD boot drive as the C: Drive.
    So remember SSD first by itself, until BIOS is correct identifying the SSD as you want it to.

    *** *** *** *** *** *** *** UPDATE *** [Feb. 4, 2014] *** *** *** *** *** *** ***
    Samsung came out with an update in the software for the Pro SSD, the "Samsung Magician Pro". It now has a feature called "Rapid Mode" and it really speeded up my Samsung 256 GB 840 to the speeds higher than indicated that they should be? But they do vary a great deal, so I am not to sure about these tests by the Samsung software. However, they are 3-4 times faster than before, with the same benchmark software?

    This is the CRAZY SPEEDS I get now (first today):
    Seq.Read 1231 (Up to 540) Seq. Write 651 (Up to 520)
    Random Read 81380 (up to 100100) Random Write 68949 (Up to 90000)
    And three weeks ago
    Seq.Read 983 (Up to 540) Seq. Write 835 (Up to 520)
    Random Read 72940 (up to 100100) Random Write 87760 (Up to 90000)
    These speeds are improved over the old speeds by 50% or 1.5 times fast to 100% or double the speed.

    Old was like:
    Seq.Read 343 (Up to 540) Seq. Write 436 (Up to 520)
    Random Read 49752 (up to 100100) Random Write 87760 (Up to 90000)

    The statement "Up to ---" is Samsung's expected speeds for this drive.
Ask a new question

Read More

SSD Storage Samsung