You'd get PCIE 2.0 X4 speeds, exactly half of the bandwidth available to a PCIE 3.0 X4 slot.
 
PCIE 2.0 has 500 MB/s of bandwidth per channel (X1).
PCIE 3.0 has 1000 MB/s of bandwidth per channel (X1).
 
PCIE 2.0 X4 has 2000 MB/s of bandwidth available, but version 2.0 has more overhead than 3.0 - so you won't see the full 2000 MB/s (just guessing, but 1500 MB/s sounds about right).
 
The difference in game load times and Windows load times from a standard, good quality, SATA III SSD to a high performance PCIE NVME SSD? ZERO, ZIP, ZILCH. You get faster file transfer speeds, and if you run a database server - very fast database access at high queue depths.
 
http://techreport.com/review/29221/samsung-950-pro-512gb-ssd-reviewed/4 
http://www.pcgamer.com/samsung-ssd-950-pro-review/ 
 
EDIT: And for the record, I have a Samsung 950 Pro 512GB NVME in a PCIE 3.0 expansion card, and I can attest to their findings. And yes, file transfers from it to my 8 drive RAID 6 array are very fast now (my game load times and my windows boot times are, sadly, the same).

A bit late to the party, but I'm installing a generic PCIe x4 NVME adapter card and a Samsung 970 EVO Plus into my EVGA X58 E762 tonight. Will run some real world tests on it. Not expecting miracles, but it's gotta be better than legacy platter hard drives by a mile. Will check back in on the thread once I have some numbers and a pic or two to post.

hehe, well it's an interesting puzzle. The main issue so far that I'm running into (and if I'd of only Googled it I'd know) is NVME and legacy bios mobos don't behave well together when it comes to making them bootable. Looking into USB boot loaders now -- Clover and Duet. Both of which have the most convoluted and confusing instructions ever. They exist, so I know it's possible. It's just that these instructions are written in such a manner as to give me nerd rage. So far 5 or 6 how-to's are most definitely not working as per instructions. I believe mostly due to them linking to sites for the boot loaders that have kept on being developed...making the old instructions...well...old (and inaccurate) 

I didn't use 970 Evo Plus with adapter card as boot drive in my X58 but I did use it briefly as data drive and in average daily workflow there was no perceived practical performance difference it and one sitting in system with PCIe 3.0. Like mentioned, it is all about workload and if your app is not creating enough I/O to saturate that bus for long time you won't be realizing any performance differences worth thinking about.

Brad_Hawthorne
The bottleneck on the X58 is drive I/O. Getting up to 850MB/s I/O on the NVME while the Ramdisk is getting up to 5,500MB/s reads and 12,000MB/s writes ...

Whether you will be able to have any real world benefit from such split is strictly dependent on type of workload distribution you will have. You will know best. In any case, figures you are getting from NVME seem much lower than they should be. I don't remember exact figures I was getting when I tried same so my memory might be playing games on me but I am under impression I was getting close to supposed bandwidth of PCIe 2.0 4 lanes. Try increasing queue depth and number of threads to make sure CPU is not your bottleneck. If that doesn't help check is your adapter card in slot that has 4 lanes and, if yes, that adapter card itself is not an issue.
 
P.S. I was under impression EVGA X58 supports only 24GB?

My guess on the NVME card is I've not got it in an optimal PCIe slot at the moment. The E762 is a bit confusing as to which slot to put it in because all the slots are 16x physical but they're all over the place as far as what speed and bandwidth they run. The E762 is PCIe 2.0 spec, so I'm not expecting too much out of it though. The NVME is definitely going to bottleneck on the PCIe 2.0 bandwidth no matter what I do. It's also why ramdisk might be more appealing because of raw I/O speed. That being said, it's splitting hairs because in real world use the NVME and the ramdisk both blow away legacy hard drives.

Brad_Hawthorne
My guess on the NVME card is I've not got it in an optimal PCIe slot at the moment.

That is entirely possible.
 

Brad_Hawthorne
The NVME is definitely going to bottleneck on the PCIe 2.0 bandwidth no matter what I do.

It will be theoretically bottlenecked by PCIe 2.0 but that bottleneck should be closer to 2GB/sec so in regular (non-benchmark) use bottleneck will be app/CPU, not disk/bus. I have 970+ in PCIe 3.0 X299 system with 10920x @ 4.3 GHz and it does benchmark what it is supposed to but in reality apps don't saturate it so actual real world figures are lower. Actually even low thread low queue count benchmark is not able to saturate it.
 
So I don't think you will end up unhappy it is PCIe 2.0 as long as you get bandwidth 2.0 can do. Otherwise, if you stay at 850 MB/sec level you could just as well drop NVME and just go with regular SATA SSD. You would be getting 550 MB/sec but you would be able to boot from it.
 
P.S. I assume you installed Samsung's NVME drivers and are not using Microsoft's Windows native ones?

Brad_Hawthorne
A bit late to the party, but I'm installing a generic PCIe x4 NVME adapter card and a Samsung 970 EVO Plus into my EVGA X58 E762 tonight. Will run some real world tests on it. Not expecting miracles, but it's gotta be better than legacy platter hard drives by a mile. Will check back in on the thread once I have some numbers and a pic or two to post.

I'm just happy you got a NVMe to work on X58. I ended up putting in 2 860EVO SATA Drives in RAID0 and was still only getting around 600MB/s due to the SATA(2). 
 
I use 3 of these NVMe/M.2 adapters on my X99 board. Now I want to test it out on the X58, I never did cause I thought it just would not work. 
I recently upgraded my 5930k to a 6950x for $200 Blem/Scratch/China/ebay CPU, I'm thinking about grabbing a 990X for around $200 for the X58 as well. it still works great for a game server and such.
I ended up running 32GB in dual channel cause triple channel kits are not so easy to find cheap.
 
I will at some point put a Samsung 980 or WD SN750 on the X58-SLI (E758)  board and see how it goes, I can just pull it out of the X99 really easy..
 

Brad_Hawthorne
My guess on the NVME card is I've not got it in an optimal PCIe slot at the moment. The E762 is a bit confusing as to which slot to put it in because all the slots are 16x physical but they're all over the place as far as what speed and bandwidth they run. The E762 is PCIe 2.0 spec, so I'm not expecting too much out of it though. The NVME is definitely going to bottleneck on the PCIe 2.0 bandwidth no matter what I do. It's also why ramdisk might be more appealing because of raw I/O speed. That being said, it's splitting hairs because in real world use the NVME and the ramdisk both blow away legacy hard drives.

I also use Primo Cache, you can setup a correct L1 / L2 Cache on your drives and make work magic. 
I found this topic to be great info.. https://forum.romexsoftware.com/en-us/viewtopic.php?t=4958 
And Dave the former Microsoft Engineer has a video here. https://youtu.be/-0Kao4TBfhQ he explains how to setup a proper cache with Romex Software.
 

Brad_Hawthorne
Here is a link to the one not working right:
https://www.amazon.com/M-...olution/dp/B07JJTVGZM?

I use 3 of these with 970 Evo Plus, 980, SN750-EK 
https://www.amazon.com/gp/product/B07GFDVXVJ
 
I look forward to hearing how this turn out if you get it to boot from the NVMe. 
 
Good luck!

Brad_Hawthorne
Now thinking my PCIe 1.0 4x issue is Windows installing the wrong hardware driver. It looks like it's using a generic Microsoft disk driver version 10.0.22000.1 dated 6/21/2006. That can't be right. I also won't let me properly install the Samsung NVME driver saying it's not valid for the drive.

Mine is the same 2006, the date really does not mean anything. 
I'm suprised I'm running windows update drivers, rather then 10.0.27 like I normally would. 
I forget why I do stuff.

Brad_Hawthorne
... the NVME adaptor card is only running at PCIe 1.0 4x but capable of PCIe 3.0 4x according to CrystalDiskInfo.

 
That would explain lower speed.
 

Brad_Hawthorne
As it's only a $12 adapter card it's no loss, but pondering what adapter card to try next to to get it properly working.

 
Card that worked fine for me in both X58 and X299 Dark is Vantec UGT-M2PC100. I also used IcyDock's card in X299 Dark with success but I didn't try it in X58.

ZoranC

Brad_Hawthorne
I also won't let me properly install the Samsung NVME driver saying it's not valid for the drive.

That's weird. Either your card is interfering or you have downloaded wrong driver. Have you tried checking what Samsung Magician is saying about drive? Which version of Windows are you running?

Samsung Magician sees the drive just fine as a genuine Samsung NVME. I'm also using the proper Samsung NVME driver installer. Might have to do with the mobo being a legacy bios mobo and not UEFI bios. The driver says on the download page "Recommended minimum system configuration is Intel Haswell Refresh Processor, 2GB RAM, 50MB free disk space and UEFI Bios v2.3." Wonder if it's not rejecting the install because no UEFI bios detected. My guess is the generic hard drive driver is defaulting the slot to PCIe 1.0 speed.
 
I'm running Windows 11 Pro 21H2 with the standard overrides to get it installed on a non-TPM mobo. I could use Windows 10 Pro, but I don't think the issue is the Windows version, but rather the lack of UEFI bios detection is rejecting the driver.

ZoranC

Brad_Hawthorne

ZoranC

Brad_Hawthorne
I also won't let me properly install the Samsung NVME driver saying it's not valid for the drive.

That's weird. Either your card is interfering or you have downloaded wrong driver. Have you tried checking what Samsung Magician is saying about drive? Which version of Windows are you running?

Samsung Magician sees the drive just fine as a genuine Samsung NVME. I'm also using the proper Samsung NVME driver installer. Might have to do with the mobo being a legacy bios mobo and not UEFI bios. The driver says on the download page "Recommended minimum system configuration is Intel Haswell Refresh Processor, 2GB RAM, 50MB free disk space and UEFI Bios v2.3." Wonder if it's not rejecting the install because no UEFI bios detected. My guess is the generic hard drive driver is defaulting the slot to PCIe 1.0 speed.
 
I'm running Windows 11 Pro 21H2 with the standard overrides to get it installed on a non-TPM mobo. I could use Windows 10 Pro, but I don't think the issue is the Windows version, but rather the lack of UEFI bios detection is rejecting the driver.

My EVGA X58 Classified3 doesn't have UEFI either yet I didn't have that problem so I wouldn't rule out Win11 as culprit. On the other hand I ran Win7 on it so UEFI can't be completely ruled out either. Do you have different (non-Samsung) NVME drive you could try? FWIW, when I tried Microsoft's generic driver in my X299 system performance was lower but not -THAT MUCH- lower, drive was still recognized as PCIE 3.0. BTW, I assume you downloaded Samsung driver straight from Samsung's support site?

I just have Samsung NVMEs. A few 960EVOs and and a 970EVO+.
 
Going to wipe and install Windows 10 Pro and see if that is some of the issue. Windows 11 locks down a bunch of stuff in the install. It wouldn't surprise me if there is something weird going on there.

Brad_Hawthorne
Could version 83 of the E762 bios be bugged with PCIe slot speeds? Grasping at straws at this point.

Impossible to speculate. But one thing that remains constant through all of this is your adapter card. Can you try different one? Also, have you tried different drive? I mean, were all these tries with 970+? If yes can you try 960?

ZoranC
 
Impossible to speculate. But one thing that remains constant through all of this is your adapter card. Can you try different one? Also, have you tried different drive? I mean, were all these tries with 970+? If yes can you try 960?

 
why do the samsung 960/970+ work over others?

harley262

ZoranC
 
Impossible to speculate. But one thing that remains constant through all of this is your adapter card. Can you try different one? Also, have you tried different drive? I mean, were all these tries with 970+? If yes can you try 960?

why do the samsung 960/970+ work over others?

I didn't say others don't work. Poster was saying he has only 960 and 970+ to test with so I was suggesting to him to try 960 if he didn't already.