OWCAccelsior S PCIe Adapter for 2.5-inch SATA 6G Expansion Card Compatible with Mac Pro (2006-2012), Mac Pro 2019 and PC Towers

Purchased this card recently for a 2009 Mac Pro 4,1.General Installation - Super easy and straightforward. Attach the SSD to the Accelsior, place it in PCIe lane 1 or 2(x16 2009 Mac Pro), close up your baby and you're done.My specific installation(you can skip this if you don't care for OWC drives or plan to use one with this card) - This is where things get interesting. I tested/used this card with a OWC Mercury Extreme 6G 480GB and a Samsung 850 EVO 500GB. The OWC SSD is being returned. Before the Accelsior S I was using the OWC SSD as my main drive. I experienced intermittent freezing and the need for hard restarts, programs quitting and a few other issues but really and truly it was intermittent. Then I got the idea of doing yet another OS X install on the Samsung EVO and I have not experienced any of the issues since. At first I did consider the possibility of a bad migration but some other symptoms the OWC displayed suggests otherwise.Using DriveDX it states that the OWC SSD now has a overall health rating of 64.3%. I have seen this number fluctuate but the mean or general reading is 64.3%. There are 17 errors and the most concerning and highest are the read/write errors. This possibly explains a few things. The drive is 8 days old and has not been abused. Putting it in any of the 4 bays or where the optical drive was, basically any sata connection, causes the computer to go into a black screen on reboot with a small loading bar in the left corner of my screen. After about a minute it finally goes to the desktop where all programs are open and the desktop is loaded. Prior to this it would load normally but then the desktop wouldn't be built. I could open programs etc but it would be a minute before the desktop would show drives, folders etc. Erasing the disk now takes longer than I have ever seen any disk take to format using Disk Utility. Those Read/Write errors? After doing some more research I decided to return the drive for a refund and got my RMA yesterday.Performance - Attached I have some BlackMagic screenshots of the read and write tests before the Accelsior with the Samsung EVO in Bay 1 and then after with it on the Accelsior. Another 50% gain but since it was needling out what were the true peaks? I used Disk Sensei and then got 540 Read and 525 Write. I'll take it! In earlier tests without the card I was only getting half the read and writes as shown in the screenshots and I knew something wasn't right. I also did some work tests involving PS and moving large 2gb, 4gb, 6gb andSo if you're looking for a performance boost I would highly recommend this card. My SSD scratch disks for programs like AE, PS etc and additional 16GB of RAM aren't even here yet and this card alone has already made a world of difference. My extremely large PS files just open now after a second. Literally. No beachballs, loading bars, nothing. It just appears.MAJOR Note - While I've only seen this affect one thing it's worth noting. The card and Samsung SSD in PCIe lane 1 is seen as an external drive. I haven't and don't want to attempt ejecting it to "see what happens". Some things like trying to eject the main drive your OS is on should probably be left to the imagination. the Same in lane 2 and for performance reasons I didn't bother testing lane 3 and 4 which are only x4. If they were x8 that might have been worth a test or two.The thing I've seen it affect is sometimes when I click into my main drive my user profile folder, application folder etc takes maybe a second to load. Very weird as I don't see this latency or pause in anything else I've done with this configuration so far.I apologize for the long winded part about the OWC drive and review in general but it's really important to cover those aspects for several reasons. If anything changes with the card, performance or otherwise I'll make some updates.

Update: after almost 2 years, it is performing flawlessly. OWC products tend to be a little more expensive but they just work. I've upgraded the drive to a 2TB Samsung 860 EVO and it is dedicated to Lightroom: Lightroom, catalog and caches.The performance results will follow but first a note to HP Workstation users. I'm on my 4th HP workstation over the past 15 years and one common factor (seems to be true of Dell Workstations as well) is that the PCI slots tend to have strange requirements. I'm talking about true workstations, not desktops. My current machine is a HP Z440 with 6-core Xeon, 64GB of ECC RAM and a HP 512GB NVMe drive (all from the factory).I've been running a Samsung 1TB 840 EVO for several years (this machine and a previous HP Z420) in an external case connected to a USB3 hub. With this configuration, it is only about twice as fast as an external hard drive. So I purchased this OWC card from Amazon as a holiday present to myself to improve the performance of the drive. However when the card is placed in PCIe Slot 3 (an X4 slot), which should work fine; the machine cannot boot up. Note that this is not the boot drive. Error 928 Fatal PCIe Error. According to HP documentation, the HP NVMe drive won't work in this slot either.Moved the card to PCIe Slot 5, an X16 slot, and the card works fine. I'm disappointed because I really wanted to run 2 of these cards in my machine, such is life.Now for the performance, keeping in mind that this drive was handicapped running through the USB3 hub.2 different performance tests:Test 1. copying a folder containing 450 files, 7 folders and 33.9GB of filesTest 2. copying a folder with a single 5.5GB fileOld configuration (SSD externally connected)Test 1 - copy from SSD to NVMe - 14min 10secTest 1 - copy from NVMe to SSD - 15min 7secTest 2 - copy from SSD to NVMe - 2min 19secTest 2 - copy from NVMe to SSD - 2min 27secNew configuration (SSD on OWC card)Test 1 - copy from SSD to NVMe - 1min 8sec == 12 times fasterTest 1 - copy from NVMe to SSD - 3min 22sec == 4.5 times fasterTest 2 - copy from SSD to NVMe - 4sec == 34 times fasterTest 2 - copy from NVMe to SSD - 4sec == 36 times faster

Lets me boot at full speeds off my 1TB Crucial MX500 SATA SSD in my ASUS P6T Deluxe V2 Intel X58 motherboard. Without the adapter and running off the motherboard's SATA II ports, the MX500 would only do about 250MB/s. With this Accelsior S adapter it goes well over 500MB/s like it should.