08-14-2019 06:29 PM
Thanks to both of you.
I turned off the PC and pulled the adapter with the added M.2 SSD out of the slot #28, and put it into #26. Rebooted. The PC was not able to negotiate with the card in this particular slot. And Windows dismgmt did not recognize the drive. I swapped it back, and all is fine again. So #26 does not work.
As for the drive naming, my CD/DVD drive is an external USB 3.0 one, and when powered up and with a disc inside, it is recognized as "I" (I didn't choose it). But for some reason, D, E, F, G, H are all not available to be chosen for the letter of the M.2. SSD. I'm okay with X, as I have a synology NAS with Y and Z being used.
08-14-2019 08:02 PM - edited 08-14-2019 10:22 PM
You must already have some other removable drives attached, which have been assigned drive letters D, E, F, etc. Perhaps a multiport USB hub or a multi-card reader or something. Windows Explorer should show you what those letters are assigned to as should DISKMGMT. Anyway, if X is OK then fine.
Can't imagine why your slot 26 didn't work. I use that slot on my M920t tower for an x1 card along with an x16 graphics card in 28 and an x1 card in the true x1 slot, and it sees my second x1 card in 26 and negotiates fine.
You should run CrystalDiskMark to confirm speed of both yourvNVMe drives.
08-15-2019 04:36 AM - edited 08-15-2019 04:38 AM
Unless I'm adding a PCIe graphics card (low profile, short length.... I know of this model's space limitations), I will not need to consider slot #26 for the M.2 SSD.
I ran DiskBenchmark,
CPU: Intel Core i7-8700 - 90.7%
SSD: Samsung MZVLB256HAHQ-000L7 256GB - 35.3%
SSD: Crucial P1 3D NVMe PCIe M.2 500GB - 228.5%
RAM: Ramaxel RMUA5180ME78HBF-2666 2x16GB - 84%
08-15-2019 02:44 PM - edited 08-15-2019 02:47 PM
I am starting to think if it's worth looking at a M.2 SSD-to-PCIe x1 adapter like this one
so it fits into the x1 slot (#27), rather than "wasting" slot #28, which can accept a graphics card if I choose to buy one in the future.
08-15-2019 03:47 PM
I'm not sure it will work with the Crucial NVMe x4 SSD that you have, but for sure even if it does you're only going to get x1 speed.
The x4 Crucial SSD is already "slow" (i.e. compared to other NVMe x4 SSD's from Samsung), as your performance screenshot shows. The CT500P1SSD8 only scored 1446 MB/s compared to your Lenovo OEM SSD (i.e. Samsung PM981) which scored 2189MB/s. That's why it's priced where it is. Both of these are "slow" compared to retail more expensive Samsung NVMe SSDs (EVO and Pro), which score 3000-3500MB/s.
So even if it would work in the x1 slot, it will be VERY slow (perhaps 1/4 its current speed), really defeating the whole purpose.
Honestly, you should be able to use your second x16 slot (26) for the x4 PCIe-to-M.2 adapter card. There's no good reason it's not working, except perhaps because of the adapter card you're using. If I were you I'd try a different adapter card in the #26 slot first, before giving up. Something like this StarTech adapter card should certainly work. Very fine company, makes lots of excellent products of all kinds at very reasonable prices.
As far as thinking about using slot #28 for a graphics card, you need to really consider that the M920s SFF case is quite small inside. This limits significantly the available choices you have for a usable low-profile card (which is required in an SFF case) that is also short enough to fit. The PSREF states maximum length of 150mm (5.90") and maximum height of 58mm (2.28"). That's a very tiny graphics card. And there's also limited power from the 180W or 210W PSU in the machine, which is also a significant limiting factor in your choice of graphics cards.
08-15-2019 06:23 PM
Thanks. I've read the posts you put up regarding challenges of fitting a graphics card into an SFF chassis, all kindly noted. Buying a graphics card used to be a "thing" with me a long time ago, now it really doesn't matter for me. I'm into photography, lightroom and photoshop are my big apps -- as long as there's plenty of RAM I'm happy. I'm already quite satisified with my Crucial M.2, coming from the world of 5400 rpm hard disks it's a big improvement.
I agree with you -- upgrading my adapter from a generic brand to StarTech is worth a shot -- whereas going to a generic 1x is counterproductive at this point. I will do that.
08-16-2019 04:12 PM - edited 08-16-2019 05:19 PM
The suggested StarTech adapter card arrived, at 160mm (6.4 inches) it is too long. (update) But it seems to be slim enough so it extended further into the area next to the DIMM slots so I guess that's fine. The bigger issue is the adapter's SSD standoff and installation screw is incompatible with the screw that came with the Crucial M.2. SSD -- the screw that came with the Crucial M.2 SSD is too short and would not extend far enough into the hole for the SSD to be secure. (It did fit the into the hole for the lesser-known brand adapter)
08-16-2019 07:03 PM
It's not the length of the StarTech adapter or the limited space of the SFF, the length is fine. It's slimmer than a Graphics Card so it was able to "borrow" some extra space next to the strips of RAM and not hitting any walls.
The only hiccup this time is the hole that holds the screw that came with the SSD, the hole was too big so the screw was unable to be tightened all the way down to gain any traction with the threads. Before returning the StarTech, maybe I will visit some computer stores and see if they have a screw that fits the hole.
08-16-2019 08:03 PM - edited 08-16-2019 08:04 PM
At 160mm in length that shouldn't be usable, as the PSREF states 150mm is the maximum card length.
As I recall when I bought a 910s SFF and tried to use a "standard" graphics card but couldn't (requiring me to return the 910s and go with a 910t instead), the issue is that even though the card seems to install properly and with no problem of "clearance" when the hinged chassis drive-bay assembly mechanism is "swung up/open" so that you can work inside the case, when you then swing-down the drive assembly to close up the case the leading metal edge of the assembly hits the top edge of the expansion card. This prevents the swing-down assembly to latch/lock closed securely by rather to sit a bit open/ajar, thereby preventing attaching the outside black metal case side. I believe the M920s SFF case is the same as the M910s SFF case, so the story should be the same here.
Now this problem may only have been true with a low-profile graphics card that probably was very close to the max height of 2.28" or maybe even just a bit higher, but perhaps is not the case with the StarTech adapter card which because its height is only 1.77" (well under the max height of 2.28"). In other words you might be right, that because of its low height its extra length slips under swung-down drive assembly chassis cage and so actually escapes the 150mm max length limitation. From the motherboard screenshot it looks like this would be the case for both #28 as well as #26.
Surely any hardware store (even Home Depot) would have a usable screw that will work in the 2280 tightening hole of the card, even if the one that came with the Crucial SSD won't. Threaded screws like this are specified either in metric (M numbers) or English (non-M) diameters, along with a number-of-threads-per-unit depth. If you bring the card with you to the store, they can try their assorted sample screws to find one which is appropriate. There should be no problem at the end of the Crucial card which most likely has a half-circle notch cutout which should allow any new screw to fasten through.
Unfortunately, StarTech support closes at 9PM ET on Friday night, and re-opens at 9PM ET on Sunday night. So they're not open at this precise minute (or else I would have called them myself). But if you try them yourself (800-265-1844) after 9PM ET on Sunday I'm sure they should be able to tell you what the diameter/thread spec is for that hole so that you can actually buy a proper tightening screw.