On Mon, May 20, 2019, 6:40 PM D. Hugh Redelmeier via talk <
talk@gtalug.org> wrote:
| From: Russell Reiter via talk <talk@gtalug.org>
| On Mon, May 20, 2019 at 11:42 AM D. Hugh Redelmeier via talk <
| talk@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$180.00 w tax for 1TB was too good to pass up.
I think it will help some. Transfer speeds aren't all that critical for me at this point but keeping things cooler can't hurt as far as EOL of the component goes.
Looks like a good choice for a drive.
Something I didn't know:
=> Thermal throttling is an issue for nearly all M.2 NVMe SSDs,
and the Crucial P1 is no exception. Not cooled and fully
loaded, it will heat up quickly and start throttling after a
bit more than a minute at full load. Now, don't get scared. In
that time, the drive processes almost 100 GB of data. Again,
=> highly unlikely in a consumer scenario. Still, I would have
wished for a higher temperature limit and a more graceful drop
in performance during thermal throttle. Samsung, for example,
has implemented that very well.
The problem I was thinking of is shown in "write intensive usage":
<https://www.techpowerup.com/reviews/Crucial/P1_NVMe_M.2_SSD_1_TB/6.html>
But they suggest it hits after 140GB of writes, not 100G you reported:
I didn't benchmark the transfer, I only observed the transfer countdown thingy in the file manager. After reading reviews of the drive some M$ 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.