GLOTRENDS PA21 Dual M.2 NVMe to PCIe 4.0 X8 Adapter Without PCIe Bifurcation Function, Support 22110/2280/2260/2242/2230 Size (PCIe Bifurcation Motherboard is Required)

As described thankyou

Works as Intended

I was apprehensive about buying this card due to the number of people saying there's "missing M.2 screws" - turns out that those people are just plain dumb 😂 the two screws in the little plastic pouch are just for mounting the card to your case.You get 3x brass grommets on the board (2 located with the M.2 slots and one on the corner of the board as a spare.) you just unscrew them from the back and the brass grommet is used to mount the M.2 drive.Reason for 4 stars, instead of 5:Overall this adapter appears to be well-made and if I had the right motherboard then I've no doubt that it would work as intended - unfortunately the instructions on this listing are poorly translated and as a result, it turns out that although my motherboard is a B450 and has Bifurcation options, it doesn't seem to have the *right kind of Bifurcation*.This means that only one of those 2 M.2 slots is recognised (M.2 Slot 1) by my motherboard. Not a big deal at the moment as my C-Drive was only a 500gb SATA-M.2 drive so I just swapped it out.Read/Write speeds of the M.2 NVME drive mounted using this adapter seem to be around the 450MB/s mark - this is obviously a lot lower than the 3500MB/s that the NVME drive is capable of but this may also just be down to my motherboard not bifurcating the PCI-E slot correctly.

After enabling bifurcation on the x8 slot on the mainboard, installing the card and two (known good) NVMe SSDs, everything appears to work great - the drives are detected in Windows, formatted and ready to go. A disk speed test appears to work fine, and copying over a few hundred gigabytes of video files completes OK. However after a period of time which ranged between 5 minutes to 1 hour, all files on the disks are corrupted and unreadable. The same thing happens with either 1 or 2 drives installed, with various SSDs and with different filesystems. Eventually I switched to another card from a different (more reputable) manufacturer and with identical drives everything is working absolutely fine. Although this could be a specific incompatibility with my particular mainboard/bios/processor/etc... I think it's unlikely.

I bought the board to improve performance on an older machine. It arrived loose in a carboard box - no protection for being dropped and so on. The big minus though was the wrong screws have been included so it's impossible to install an M2 SSD. The screws are far too big to fit the holed in the mounting pillar and so I'm sending it back for a refund.

Bifurcation doesn't work and as a standard single NVME disk, it only provides SATA read/write (300 to 500mbs) way below the advertised 3500mbps. Also, it corrupted the disk already with files. Avoid at all cost!

Got the item but missing M.2 screws to hold down the SSD`s.Surely these should be supplied with the adaptor, just like they are for mobos.Cant try it out until sorted.I have contacted Glotrends for an answer but until then i have to give one star though should be zero until sorted out.

My setup consists of5950xX570s Aorus Master6900 XT32 GB 3600 MHzWin 10 with the latest updates as of 16/8/2022This adapter is in the 2nd slot which is a x8 which is also PCIE 4.0. Attached with an Intel 670p and Western Digital Black SN750 SE both 1 TB.The drives used to test the adapter are Samsung 980 Pro 2 TB and a Corsair Force MP510 960 GB.There were some issues, one of my own making and the other from the adapter. Firstly my mistake was that I have a lot of mapped networks, so the 2nd drive wasn't being detected as one of my mapped networks already was assigned that letter. Once that was sorted, both drives popped up after restarting Explorer. Adapter issue. I had to bend the PCIE metal cover slightly so it would actually slot in place, as otherwise it would just sit there and made everything quite lose which wasn't ideal. It was a simple fix that took me about 5 min to figure out.I've just finished my testing of running 2x 1 TB NVME PCIE 3.0 Drives with crystaldiskmark and transferring a 53 GB file. Both tests done simultaneously. Before testing both, I did individual testing, so to see if there was any loss in speed.Random writes while testing both with crystaldiskmark simultaneously resulted in a 20-50% loss of speed during random testing however all other results were the same (within margin of error).Transferring with both recieving and sending, they are slowed down a lot and have the same dips in speed, however the faster and mostly empty drive seemed to possibly pick up the slack of the 60% filled NVME, as when sending data simultaneously, the slower drive was actually 65% faster than when sending data solo. When sending data, they didn't seem to like sending it to the same drive, so had to split it and they were about 30% slower when sending data simultaneously but this was still sending a total of 106 GB of data in about 32 seconds.Sidenote. The WD NVME was able to send thermal, speed and utilisation data in real time through the adapter whilst the Intel NVME isn't. So this is why I didn't report any thermals and not everyone has the same case layout, ambient temperature, Etc as me anyway. But for what it's worth, the WD NVME hit a max of 73c during crystaldiskmark in a 28c ambient room with a closed case that has 13 fans in total although most being covered by radiators. I'm aware the WD NVME is PCIE 4.0 but it's speeds, Etc are quite similar to the SN750, So I don't consider it an actual PCIE 4.0 NVME but it is in the upper end for speed among the PCIE 3.0 NVME.This is only day 1. So if there's any real significant changes, I'll update this review.