NVMe drives include an emulator for the AHCI accesses necessary before transitioning into NVMe modes. This does not slow them down. Performance is limited by two things: (1) the speed of the flash ICs used in the drives and (2) in the case of the KY NUC, throughput is limited somewhat by the performance limitations of the DMI bus -- but this is only a factor if you have two NVMe drives utilizing the full PCIe x4 bandwidth...
Hope this helps,
Thank you Scott. I really appreciate your input!
I am going to put 2 NVMe drives (most likely the Samsung SM961) in single or RAID 0 configuration so I am wondering what the NUC6i7KYK DMI bus speed is that can limit the throughput of the NVMe drives.
Also I am wondering if the NUC6i7KYK is able to boot from an external SSD drive without having any OS installed in the internal drives. If it is impossible, I am wondering if you are aware of any possibility to connect an SSD to the NUC using an adapter like this
In such case the external SSD will act as an internal drive so the NUC will be able to boot Windows 10 from it. The only problem I see in this case is the power to the drive that will probably be an external connector because I cannot find any internal power connector.
There is another conversation here somewhere wherein someone did the math and concluded that the DMI bandwidth was insufficient to completely support two 950Pro NVMe drives running flat out in RAID 0. The performance tests they (also) ran backed up their conclusions. Now, the SM961 NVMe drives are slower drives (use slower flash silicon - and this is reflected in their lower price) and you may have the bandwidth to get some benefit from using RAID0 with them. Frankly, I have concluded that using RAID on the KY units is (only) beneficial if you are either using RAID1 to maintain a backup (mirror) drive or your are using RAID1 to accelerate a pair of M.2 SATA SSDs, but I guess that using RAID0 to make two NVMe drives look like one big drive does offer a simplicity benefit...
Another customer reported that he has had some success using one of these adapters. He didn't say whether he successfully booted from this drive, but I believe that the NUC should be able to do so. Since the adapter is just exposing the chipset SATA lane that is provided in the mPCIe connector, the BIOS will not see much difference between a local M.2 SATA SSD and an external SATA SSD connected to this adapter.
Obviously, using one of these adapters, there will be issues with Z-Height and you won't be putting the lid (base) back on with this adapter (and SATA cable) attached.
When I was experimenting with this kind of adapter (but with a much older NUC and an adapter that plugged into a mSATA connectors), I used a separate power brick that came with a USB-to-SATA adapter and it powered the (3.5") HDD that I connected without issue.
Hope this helps,
From a different point of view - are you seeing any disk queuing or Split I/Os ? If so, how much and when?
RAID-0 is faster than non RAID, but if there is no bottle neck why go for faster?
Are you seeing any split I/O's ? If so, RAID-0 can help fetch both parts of the file to satisfy the I/O request. However there are ways to defrag the data both logically and physically.
Also, is your CPU clock speed running at 2.0 Ghz or higher? CPU will slow down when things are not going on. This causes slow response. Not because the memory, disks or mother board are slow but because the CPU is running at 800Mhz in "idle" mode.
Lastly, using as many disks as possible helps identify which file is the issue and group stuff together the best way possible. However I work with databases and not games.
Asking questions and giving insight for over forty thousand years
Thank you Scott and TechnoCaveman.
I wanted to use RAID 0 in order to speed up the drive performance but really if the DMI bandwidth is insufficient there is no point for me using it. RAID 1 is more secure but slower than RAID 0 and because I am looking for speed, it is not good for me. So it is for I/O speed rather than security.
The SM961 has it pluses and minuses - faster in sequential reads than 950Pro but slightly slower in random but only at higher queues so overall it is faster than the 950Pro. It is made from 48-layer MLC V-NAND that has more capacity than the 950Pro 32-layer MLC V-NAND. I thought to use it mostly because of its high capacity (1Tb max vs 512GB of 950Pro).
In regards to the external SSD I think it will be easier to use fast external drive like the Samsung T3 than the adapters because as far as I can see both will perform nearly at the same speeds and the T3 does not need any adapter and external PSU.
PC World reviewed some thuderbolt SSD and NVMe drives which might be faster than Samsung T3
Five Thunderbolt Devices for Lightning-Fast Data Transfers | PCWorld
If they give you another drive letter, then you get another I/O queue and metrics on where the bottle necks may be.
(sound of jaw hitting desk [again]) in a romm full of silence)
I had to read the spec sheet twice. Missread 2100 as 210, not 2,100
Also " or at the end of a Thunderbolt 3 device daisy chain" implies multiple drives for multiple I/O drives.
Smart TVs with quad core processors, smart phones with eight cores. toilets with iPhone apps (and a really bad security flaw). All of this is wilder than Issac Asimov's science fiction book "Caves of Steel" where people live in isolation; interacting only through the main frame terminal in their homes. Putting in my wish for Rock Band 5 VR game simulating me playing with Jimmy Hendrix, Pat Benetar, Janice Joplin, "Animal" on drums and "Lars Oomlat" at the Holly wood bowl in realistic 4K.
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Thanks for the information, also here are some steps to setup the RAID configuration: https://www-ssl.intel.com/content/www/us/en/support/boards-and-kits/000021493.html
Ran99, please let us know the outcome.
How the guy from Babylon 5 said: "The future is not how it used to be..."
I already read the RAID setup before but thank you anyway.
Here is a good place to see most Thunderbolt products on the market today: https://thunderbolttechnology.net/products
Good quote from "Babylon 5" While 50th anniversary panles at ComiCon talk about the tech they inspired, there is so much more. We can create it.
Thank you for the Thunderbolt information. I may go "Matrix" style and add a few more displays as things converge (XBox, FireStick, Multi display NUC)
I wonder if Intel is surprised so many folks use their TV as the main monitor or monitors ?? Yes, very Comodore-64
Hopefully I'll get some computer time tonight (no robots to clean the cave & man cave, clean cloths or run errands. [Tech note: Neanderthals gave to the poor and injured - a.k.a. paid taxes ])
To stay on topic - ACHI SSD in the NUC 6i7 are very fast!! ACHI formatted PCIe to PCIe 30 gig file transfer was done in twenty seconds or so.Took me a while to find a backup big enough to challenge the little guys. I am soo happy.
"Burn the land and boil the sea - I'm still free. You can't take the sky from me"
Good to hear about the AHCI SSD but I am wondering why Intel did not use direct NVMe instead (maybe it may create a bottleneck?).
In regards to monitor - yes it is funny that TV is becoming A monitor. But if you remember - Bill Gates wrote about it in his book 15 years ago, so as Captain Picard said "The future is now!".
Also 90% of today PC users are gamers or Internet browsers that really has nothing to do professional computing and buying 4K TV becase the shop salesman advice them without even understanding that they can see only content in 4K from Netflix or alike in very rare cases. Same people are buying 4K monitors for browsing the internet in 1080p, enlarging the fonts by 250%. Hmmm, so why they paid 3 times more for product they never use as intended? But the funniest case are the desktops with 27" screens - "All in one" - and... with 1080p maximum screen resolution. Yes 1080p!!! I could not believe it until I've seen this last week! One will probably need a minimizing glasses to sit 60cm from it without getting a severe headache!
So yes, Commodore-64 and Atari are still the kings!
BTW, on a serious note - have you ever seen 25" monitor with 2560x1440 resolution? Something like the Dell U2515H. I wondering if it will be good replacement from 1920x1200?