[GTALUG] NUC NUC NUC

[Russell Reiter]

On Mon, May 20, 2019 at 11:42 AM D. Hugh Redelmeier via talk <
talk at gtalug.org> wrote:

> | From: Russell Reiter via talk <talk at gtalug.org>
>
> | Optane was intended to be a cache memory to increase the performance of
> | conventional spinning HD's under Windows OS. However, I've been booting
> | Fedora from both a 500gb SSD and 32gb Optane Nvme as I tinker with my own
> | desktop.
>
> I think Optane is just a brand name and that brand name gets attached
> to several different things, some of which are not yet being sold.
>

True enough, sometimes it's hard to sort specifications from hyperbole.

>
> The original promise was: non-volatile memory that would get speed
> close to RAM and price close to flash.  (They also need better
> durability than flash.) There's a big gap between those, and anything
> in between ought to have a market.  They just haven't been able to
> accomplish much.
>
> - they wanted to produce things that fit in RAM sockets.  That meant
>   either
>
> (1) no change from RAM interface (unlikely, but suggested-by-omission
>     in early marketing) or
>
> (2) memory interfaces that were augmented to support the new protocols
>     (delivered with some new Xeons, I think)
>
> - the NVMe stuff has had much worse durability than originally
>   promised.
>
> - the NVMe stuff has had quite small capacity compared with most SSDs
>
> - NVMe SSD has mostly been fast enough that the Optane stuff isn't
>   compellingly better
>
> | Most certainly booting to a login prompt is fractionally quicker
> | on the Nvme than on the conventional SSD.
>
> That's what I'd expect.  But I'll admit to no experience with Optane
> and I haven't been following it closely.
>
> |  However recently I up-sized my
> | Nvme and have populated my M.2 slots with a 250gb WD black Nvme for boot
> | and now added an additional 1TB to the second M.2 slot with F29 still on
> | the SSD. Copying a 100gb image to the 1TB drive really hit performance
> tho
>
> 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.
>
> You can pay more and get SSDs with enough RAM to not have this
> performance problem.  I don't know enough to give specific advice.
>
> I have recently learned that some cheap NVMe drives can ask the OS to
> allocate system RAM for the exclusive use of the controller.  This
> isn't a conventional data cache, but something much stranger.  It's
> called "Host Memory Buffer" (HMB).  I think that vendors don't explain
> it because they think consumers won't understand it.
>
> HMB might be a great trade-off, or a horrible hack.  I don't know.
> What happens when the power fails?  Or when the system crashes /
> reboots?
>
> Recent Linux and Windows support HMB.  I assume that UEFI firmware does
> not.  So use of HMB must be an optional speed-up.
>
> | and that was probably due to the lack of a decent heat sink.
> | I just ordered a hteatsink fro the internal 1TB
>
> 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

https://www.techpowerup.com/reviews/Crucial/P1_NVMe_M.2_SSD_1_TB/7.html



> | Perhaps with the NUC form factor heat might
> | be a problem on a larger sized Nvme but with USB-C you have wiggle room
> for
> | adaptation.
>
> The NUC form factor certainly reduces the heat disposal and thus
> limits components.  But the main such component is the CPU.  I've not
> heard of it being a problem for consumer 3.5" SSDs (what Evan intends
> to use) or NVMe drives.
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-- 
Russell
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