On Mon, May 20, 2019, 6:40 PM D. Hugh Redelmeier via talk <[email protected]> wrote:
> | From: Russell Reiter via talk <[email protected]> > > | On Mon, May 20, 2019 at 11:42 AM D. Hugh Redelmeier via talk < > | [email protected]> 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. --- > Talk Mailing List > [email protected] > https://gtalug.org/mailman/listinfo/talk >
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