[GTALUG] NUC NUC NUC

Tue May 21 07:37:37 EDT 2019

On Mon, May 20, 2019, 6:40 PM D. Hugh Redelmeier via talk <talk at gtalug.org>
wrote:

> | From: Russell Reiter via talk <talk at gtalug.org>
>
> | On Mon, May 20, 2019 at 11:42 AM D. Hugh Redelmeier via talk <
> | talk at gtalug.org> wrote:
>
> | > Why do you think that this was heat-related?  It might be, but that
> | > would not be my first guess.  (I am not an expert on this.)
> |
> | Apparently, at least on Crucial products, there is built in thermal
> | monitoring which will throttle speeds.
> |
> | Here's a link to the 1TB Nvme. On sale for the next few days for $147.00,
> | about $40.00 less than I paid.
> |
> |
> https://m.newegg.ca/crucial-p1-1tb/p/N82E16820156199?item=N82E16820156199&m_ver=1
> |
> | Here's a link to a review of Crucial's Thermal Throttling capacities
>
> Wow, prices sure have dropped.  (I wish I had more sockets that would
> take NVMe.)
>

It's the price drop which made me change my build plan. I was going to have
just one SSD for boot and install xTB Sata disk drives. I tried out M.2
just because I could. 90$ (tax inc.) for 32gb seemed ok for fun. Then I put
250gb in slot 2 so I could run multiple versions of Fedora while I came to
terms with learning about systemd and dealing with recent fencing in side
channel attack mitigations. For the last year the z370 issued so many
firmware updates, I stopped doing them til last month.

However$180.00 w tax for 1TB was too good to pass up.

>
> | https://www.techpowerup.com/reviews/Crucial/P1_NVMe_M.2_SSD_1_TB/7.html
>
> Thanks.  Quite interesting.  I hope your heat sink helps.
>

I think it will help some. Transfer speeds aren't all that critical for me
at this point but keeping things cooler can't hurt as far as EOL of the
component goes.

>
> Looks like a good choice for a drive.
>
> Something I didn't know:
>
> =>      Thermal throttling is an issue for nearly all M.2 NVMe SSDs,
>         and the Crucial P1 is no exception. Not cooled and fully
>         loaded, it will heat up quickly and start throttling after a
>         bit more than a minute at full load. Now, don't get scared. In
>         that time, the drive processes almost 100 GB of data. Again,
> =>      highly unlikely in a consumer scenario. Still, I would have
>         wished for a higher temperature limit and a more graceful drop
>         in performance during thermal throttle. Samsung, for example,
>         has implemented that very well.
>
> The problem I was thinking of is shown in "write intensive usage":
>
> <https://www.techpowerup.com/reviews/Crucial/P1_NVMe_M.2_SSD_1_TB/6.html>

> But they suggest it hits after 140GB of writes, not 100G you reported:
>

I didn't benchmark the transfer, I only observed the transfer countdown
thingy in the file manager. After reading reviews of the drive some M$
users said transfer speed dropped off at around 50gb. My 100gb was me
clearing up the WD drive in preparation for Fedora 30, which it is running
now.

>
> | > | the SSD. Copying a 100gb image to the 1TB drive really hit
> performance
> | > tho
>
> You can see a very large performance cliff at 140GB.
>
> So either what you are observing is not this cliff, or you are doing
> something else (reading the image from the drive?) to move the cliff
> earlier.
>
> The heat cliff should be much much sooner, I think.
>
> Their diagram showed the thermal cliff happened (without any fan)
> after about 60 seconds of 160MB/s writing.  That would be about 96GB.
> Funny that you'd notice that with a 100GB image since only the last
> 4GB should be slow.  That should only take another 7 or 8 seconds
> (instead of 2.5 seconds).  That isn't something I'd notice.
>

The last few seconds were at 98mb. I didn't actually observe the first few,
but in the middle I saw transfer speed start to drop.

>
> Copying a 200 GB image should be a LOT slower than a 100 GB image (if
> there is no fan).  The second 100GB should take almost 200 seconds.
>
> After 140GB, the caching cliff should hit.  Surprisingly, this doesn't
> show up in the article's Thermal Throttling graphs.

> There's something fishy here.
>
> | > SSDs come with different performance trade-offs.  Most inexpensive
> | > SSDs have (on-board) controllers with only small amounts of RAM.  This
> | > makes them slow down a lot after a modest burst of intensive writing.
> | > That's a fine trade-off for many of us but not for all workloads.
>
> The Crucial drive has a 1 GiB RAM chip onboard, not like the cheap ones
> I was thinking of.
>
> I think that the cliff for cheap ones comes much earlier, due to
> running out of mapping RAM.
>

Thanks for the link. I had a quick glance and I'll read in depth later.

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