4 ms·
1) Nobody says otherwise about cheap anything NVMe. They're pretty terrible once they've exhausted the write cache. This is well-known and addressed in every de
by Sakos 3y ago
1) Nobody says otherwise about cheap anything NVMe. They're pretty terrible once they've exhausted the write cache. This is well-known and addressed in every decent review by reputable sites.
2) Sustaining throughput seems the least of our problems when some unknown number of NVMe SSDs might be literally losing flushed data.
- kristopolous 3y agoIs this expected with say Samsung evo 9X0 pro? Or is there another tier above consumer level gear? Is there something I should go with?
- vladvasiliu 3y agoI don't know about the 950 pro specifically, but when I bought my 980 pro I looked into this, and it seemed that this drive does have a drop in write speed after a while (can't remember how long) but "low speed" wasn't that low. Again, don't remember specifics, but it was above 1 GB/s. Other drives fared much worse, with a drop coming in sooner and going lower. Depending on your needs this can be an issue. For me, using this drive for random "office" work, I figured I'd never feel it in practice. This drive is supposed to support PCIE 4, but my laptop only does 3. This also "helps", since it won't fill whatever cache it uses as quickly. In practice, it was able to write 100 GB at the top speed. Didn't bother to test more. The only time I've ever written that many data at a time was restoring a backup when I bought the drive. Since my backup was on 2.5" spinning rust, it wasn't an issue.
- kristopolous 3y agoThanks. I guess I can't really blame them for cutting corners on a use case that 99.9% of their customers never see. I'd probably advocate the same.
- vladvasiliu 3y agoI think it's important to be able to have a rough idea of how you'd be using this. If this drop in performance means I could use a cheaper drive, I'm all for it. But some drives are truly awful. My work laptop came with a cheap Samsung drive that would quickly drop to around 200 MB/s. At first, I thought I had somehow badly configured Linux or something (I'm running zfs with native encryption). Then I went and checked my desktop running quite worn-out SATA ssds from ~2012 (840 evo) and those drives would wipe the floor with the NVMe in write performance. They wouldn't go below 400 something MB/s until almost full. Same kernel version and zfs config. It would seem that this is quite common behavior in cheap drives. But I guess that if all you do is browse the web, write mails in outlook and type the occasional word document, you're still ahead of spinning rust for the durability (it won't break if you drop your laptop) and for the latency.
- kristopolous 3y agoIn my use case I'm talking about arrays of them, think 8. RAID can parallelize platter really nicely in that configuration. But on modern ram/cpu (epyc 9654s), you'll still see the disk dragging you down. NVME drags me down more. Maybe the key is a bunch of small ones. Like 20 512GB modules... That may be brilliant. It's way cheap
- vladvasiliu 3y agoThat sounds like you might be having quite specific needs. Some reviews have graphs showing how the drives behave in various situations, so that could help you. However, what I've found perusing those reviews is that there's a huge price gap between this class of drives (9x0 pro, wd 8xx and the like) and "enterprise" drives which seem to have more stable performance.
- kristopolous 3y agoRight. I'm just an unemployed guy with expensive hobbies
- Sakos 3y ago